SymPy was started in August 2006 by Ondrej Certik. Since then, a toy like project grew considerably and many people contributed to it. As of beginning of December 2011 there have been over 150 people who contributed at least one commit to SymPy (see AUTHORS file in SymPy’s repository for details). SymPy itself consists of over 200k lines of code spread across 26 modules. The GIT history of SymPy contains more than 7000 commits, although early history wasn’t imported from SVN due to technical difficulties.
Since 2007 SymPy participates in Google Summer of Code. This program was a great opportunity for the project to get massive development over summers. During five years of participation in the program there were 24 students working on different aspects of SymPy:
Only one student failed his project. In 2011 SymPy was for the first time a mentoring organization. In the previous years SymPy participated under the umbrella of Python Software Foundation, Portland State University and Space Telescope Science Institute. Both authors of this tutorials were GSoC students at some point, Mateusz in 2007 and Aaron in 2009 and 2010.
SymPy also have participated in Google’s programs for precollege students: Highly Open Participation Contest in 2008 and Code–In in 2011, having often excellent contributions from young (13-17 years old) participants.