I'm a big fan of the Google Summer of Code. It brings great projects together with a learning opportunity for students. Once again the R Project was selected to be part of the Google Summer of Code in 2011. Some other notable mathematical and statistics projects with R include Shogun Machine Learning, SymPy, Gambit, Computational Geometry Algorithms Lab, Orange, and Computational Science and Engineering.
The Google Summer of Code has really grown over the years. I'm glad to see that these open source initiatives really help teach our younger generation.