Python is rising in popularity and may well become the most popular and used language in the world! It is not only used by small start ups but also by big corporations like google, dropbox and instagram to build their sites. One reason for its popularity lies in the simplcity of its code but it is still a very powerful language indeed. From everything from game design to high end application development, Python will do the job!
VIDEO Further uses of Python in the real world
Integrated development environments for Python
Atom, a open source cross-platform IDE with autocomplete, help and more Python features under package extensions. Boa Constructor, a
cross-platform IDE for Python development
EasyEclipse, an open source IDE for Python and other languages
Eclipse with the Pydev plug-in. Eclipse supports many other languages as well.
Eric, an IDE for Python and Ruby
Geany, IDE for Python development and other languages
Koding a free online development environment for many programming languages including Python.
Komodo IDE an IDE for Python, Perl, PHP and Ruby
NetBeans, is written in Java and runs everywhere where a JVM is installed.
Ninja-IDE, free software, written in Python and Qt, Ninja name stands for Ninja-IDE Is Not Just Another IDE
PIDA, open source IDE written in Python capable of embedding other text editors, such as Vim
PyCharm, a proprietary and Open Source IDE for Python development
PyScripter, Free and open-source software Python IDE for Windows.
PythonAnywhere, an online IDE and Web hosting service
Python Tools for Visual Studio, Free and open-source plug-in for Visual Studio.
Stani's Python Editor (SPE), a cross-platform IDE for Python development
Sublime Text, a text editor.
Webware for Python, a suite of programming tools for constructing web-based applications in Python
Wing IDE, cross-platform proprietary with some free versions/licenses IDE for Python Python package managers and Python distributions
Anaconda, Python distribution with
conda package manager
Enthought, Enthought Canopy Python with Python package manager
pip, package management system used to install and manage software packages written in Python Applications
A-A-P, a tool used to download, build and install software via Makefile-like "recipes"
Anki, a spaced repetition flashcard program
Ansible, a configuration management engine for computers by combining multi-node software deployment and ad hoc task execution
Bazaar, a free distributed revision computer control system
BitBake, make-like build tool with the special focus of distributions and packages for embedded Linux cross compilation
BitTorrent, original client, along with several derivatives
Blender, 3D art and animation program with a game engine. Allows for Python scripting in the game engine and in modelling and animation.
Buildbot, a continuous integration system
Buildout, a software build tool, primarily used to download and set up development or deployment software dependencies
Calibre, an open source e-book management tool
Chandler, a personal information manager including calendar, email, tasks and notes support that is not currently under development
Cinema 4D, a 3D art and animation program for creating intros and 3-Dimensional text. Has a built in Python scripting console and engine.
Conch, implementation of the Secure Shell (SSH) protocol with Twisted
Deluge, a BitTorrent client for GNOME
Dropbox, a web-based file hosting service
emesene, a MSN/WLM substitute
Exaile, an open source audio player
Gajim, an instant messaging client for the XMPP protocol
GlobaLeaks, an open-source whistleblowing framework
Gramps, an open source genealogy software
Gunicorn, a pre-fork web server for WSGI applications
Gwibber, a microblogging client
GYP (Generate Your Projects), a build automation tool (similar to CMake and Premake) designed to generate native IDE project files (e.g., Visual Studio, Xcode, etc.) from a single configuration
Image Packaging System (IPS), an advanced, cross-platform package management system primarily used in Solaris and OpenSolaris/ illumos derivatives
Juice, a popular podcast downloader
Mercurial a cross-platform, distributed source management tool
Miro, a cross-platform internet television application
Morpheus, file-sharing client/server software operated by the company StreamCast
MusicBrainz Picard, a cross-platform MusicBrainz tag editor
Nicotine, a PyGTK Soulseek client
OpenLP, lyrics projection software
OpenShot Video Editor
OpenStack, a cloud computing IaaS platform
Pip, a package manager used to install and manage Python software packages such as those from the Python Package Index (PyPI) software repository
PiTiVi, a non-linear video editor
Portage, the heart of Gentoo Linux, an advanced package management system based on the BSD-style ports system
PyGopherd, a modern Gopher web server that also supports HTTP and WAP
Quake Army Knife, an environment for developing 3D maps for games based on the Quake engine
Quod Libet, a cross-platform free and open source music player, tag editor and library organizer
Resolver One, a spreadsheet
SageMath, a combination of more than 20 main opensource math packages and provides easy to use web interface with the help of Python
Salt, a configuration management and remote execution engine
SCons, a tool for building software
Shinken, a computer system and network monitoring software application compatible with Nagios
Tryton, a three-tier high-level general purpose computer application platform
Ubuntu Software Center, a graphical package manager, installed by default in Ubuntu 9.10 and higher
Wicd, a network manager for Linux
WikidPad, a free wiki-like outliner for personal thoughts, ideas, to-do lists, contacts, etc. with wiki-like linking between pages.
YUM, a package management utility for RPM-compatible Linux operating systems
Waf, a build automation tool designed to assist in the automatic compilation and installation of computer software
Xpra, a tool which runs X clients, typically on a remote host, and directs their display to the local machine without losing any state Web applications
Allura, an ASF software forge for managing source code repositories, bug reports, discussions, wiki pages, blogs and more for multiple projects
Bloodhound, an ASF project management and bug tracking system
ERP5, a powerful open source ERP / CRM used in Aerospace, Apparel, Banking and for e-government
Kallithea, a source code management system
Mailman, one of the more popular packages for running email mailing lists
MoinMoin, a wiki engine
OpenERP, new name Odoo, an open source comprehensive suite of business applications
Planet, a feed aggregator
Plone, an open source content management system
Roundup, a bug tracking system
Tor2web, an HTTP proxy for Tor Hidden Services (HS)
Trac, web-based bug/issue tracking database, wiki, and version control front-end
Turntable.fm, a discontinued social media site for interactively sharing music
ViewVC, a web-based interface for browsing CVS and SVN repositories Video games
BlueBream, a rewrite by the Zope developers of the Zope 2 web application server
Bottle, A fast, simple and lightweight WSGI micro web framework
CherryPy, an object-oriented web application server and framework
Django, an MVC (model, view, controller) web framework
Flask, a modern, lightweight, well-documented microframework based on Werkzeug and Jinja 2
Google App Engine, a platform for developing and hosting web applications in Google-managed data centers, including Python.
Grok, an web framework based on Zope Toolkit technology
Nagare, a web framework for developing web applications in Stackless Python
Nevow, a web application framework originally developed by the company Divmod
Pylons, a lightweight web framework emphasizing flexibility and rapid development
Pyramid, is a minimalistic web framework inspired by Zope, Pylons and Django
Python Paste, set of utilities for web development that has been described as "a framework for web frameworks"
Quixote, a framework for developing Web applications in Python
RapidSMS, a web framework which extends the logic and capabilities of Django to communicate with SMS messages
Spyce, a technology to embed Python code into webpages
TACTIC, a web-based smart process application and digital asset management system
Tornado, a lightweight non-blocking server and framework
TurboGears, a web framework combining SQLObject/ SQLAlchemy, Kid/ Genshi, and CherryPy/ Pylons
web2py, a full-stack enterprise web application framework, following the MVC design
Webware for Python, an object-oriented web application framework
Zope 2, an application server, commonly used to build content management systems Graphics frameworks
Kivy, open source Python library for developing multitouch application software with a natural user interface (NUI).
PyGTK, a popular cross-platform GUI library based on GTK+; furthermore, other GNOME libraries also have bindings for Python
PyQt, another cross-platform GUI library based on Qt; as above, KDE libraries also have bindings
PySide, an alternative to the PyQt library, released under the BSD-style licence
Tkinter is Python's de facto GUI it is shipped in most versions of Python and is integrated in the IDLE. It is based Tcl command tool.
wxPython, a port of wxWidgets and a cross-platform GUI library for Python Scientific packages
Astropy, a library of Python tools for astronomy and astrophysics.
Biopython, a Python molecular biology suite
graph-tool, a Python module for manipulation and statistical analysis of graphs.
Orange, an open-source visual programming tool featuring interactive data visualization and methods for statistical data analysis, data mining, and machine learning.
NetworkX, a package for the creation, manipulation, and study of complex networks.
SciPy, a library of scientific and numerical routines
scikit-learn, a library for machine learning.
TomoPy, a package for tomographic data processing and image reconstruction
Veusz, a scientific plotting package
VisTrails, a scientific workflow and provenance management software with visual programming interface and integrated visualization (via Matplotlib, VTK).
Apache Singa, a library for deep learning. Mathematical libraries
Mathics, an open-source implementation of the Mathematica programming language
Matplotlib, an extension providing MATLAB-like plotting and mathematical functions
NumPy, a language extension that adds support for large and fast, multi-dimensional arrays and matrices
Plotly is a scientific plotting library for creating browser-based graphs.
SageMath is a large mathematical software application which integrates the work of nearly 100 free software projects.
SymPy, a symbolic mathematical calculations package Additional development packages
Cheetah, a Python-powered template engine and code-generation tool
Cherry, a non-WYSIWYG templating language developed for CherryPy framework
Construct, a python library for the declarative construction and deconstruction of data structures
Genshi, a template engine for XML-based vocabularies
IPython, a development shell both written in and designed for Python
Jinja, a Python-powered template engine, inspired by Django's template engine
Kid, simple template engine for XML-based vocabularies
Mako, a non-XML template library which compiles into Python modules for maximum performance
mod_python, an Apache module allowing direct integration of Python scripts with the Apache web server
PyObjC, a Python to Objective-C bridge that allows writing OS X software in Python
Robot Framework, a generic test automation framework for acceptance testing and acceptance test-driven development (ATDD)
Setuptools, a package development process library designed to facilitate packaging Python projects by enhancing the Python distutils (distribution utilities) standard library.
Sphinx, which converts reStructuredText files into HTML websites and other formats including PDF, EPub and Man pages
SQLAlchemy, database backend and ORM
SQLObject, an ORM for providing an object interface to a database
Storm, an ORM from Canonical
Topsite Templating System, another Python-powered template engine
Twisted, a networking framework for Python
VPython, the Python programming language plus a 3D graphics module called Visual Embedded as a scripting language
Python is, or can be used as the scripting language in these software products:
Abaqus (Finite Element Software)
ArcGIS, a prominent GIS platform, allows extensive modelling using Python
Autodesk Maya, professional 3D modeler allows Python scripting as an alternative to MEL as of version 8.5
Autodesk Softimage (formerly Softimage|XSI)
BioNumerics a bioinformatics software suite for the management, storage and (statistical) analysis of all types of biological data.
Boxee, a cross-platform home theater PC software
Corel Paint Shop Pro
Claws Mail with Python plugin
EventScripts, plugin for Valve's Source engine
GNAT The GNAT programming chain tool (Ada language implementation in GNU gcc), as a GNATcoll reusable components for the applications (with or without PyGTK) and as a scripting language for the commands in the GPS programming environment
Houdini highly evolved 3D animation package, fully extensible using python
Inkscape, a free vector graphics editor
MeVisLab, a medical image processing and visualization software, uses Python for network scripting, macro modules, and application building
Minecraft: Pi Edition (game)
MSC.Software's CAE packages: Adams, Mentat, SimXpert
MySQL Workbench, a visual database design tool
Notepad++ has a plugin named PythonScript that allows scripting Notepad++ in Python
Nuke (compositing for visual effects)
ParaView, an opensource scientific visualization software
Poser, a 3D rendering and animation computer program that uses for scripting a special dialect of Python, called PoserPython
PyMOL, a popular molecular viewer that embeds Python for scripting and integration
QGIS uses Python for scripting and plugin-development
Rhinoceros 3D version 5.0 
3DSlicer, medical image visualisation and analysis software. Python is available for algorithm implementation, analysis pipelines, and GUI creation.
SPSS statistical software SPSS Programmability Extension allows users to extend the SPSS command syntax language with Python
Totem, a media player for the GNOME desktop environment
WeeChat, a console IRC client Commercial uses
CCP hf uses Stackless Python in both its server and client side applications for its MMO Eve Online 
NASA is using Python to implement a CAD/ CAE/ PDM repository and model management, integration, and transformation system which will be the core infrastructure for its next-generation collaborative engineering environment . It is also the development language for OpenMDAO, a framework developed by NASA for solving multidisciplinary design optimization problems. "Python has been an important part of
Google since the beginning, and remains so as the system grows and evolves. Today dozens of Google engineers use Python." 
reddit was originally written in Common Lisp, but was rewritten in Python in 2005 
Yahoo! Groups uses Python "to maintain its discussion groups"
YouTube uses Python "to produce maintainable features in record times, with a minimum of developers" 
Enthought uses python as the main language for countless custom applications in Geophysics, Financial applications, Astrophysics, simulations for consumer product companies, ...
EDF uses Python for their finite element solver Code Aster in combination with Fortran Python implementations
CPython – The reference implementation, written in C89
Cython is a programming language to simplify writing C and C++ extension modules for the CPython Python runtime.
IronPython – Python for .NET and Mono platforms
Jython – Python coded in Java
PyPy – Python (originally) coded in Python, used in conjunction RPython, a restricted subset of Python that is amenable to static analysis and therefore a JIT.
Stackless Python – Python with coroutines
CLPython – Implementation, written in Common Lisp
Pyston - an open source Python implementation using JIT techniques. Currently targeting Python 2 support.
Parrot – Virtual machine being developed mainly as the runtime for Perl 6, but with the intent to also support dynamic languages like Python, Ruby, Tcl, etc.