FizzBuzz Enterprise Edition is a no-nonsense implementation of FizzBuzz made by serious businessmen for serious business purposes.

Educational Proof Assistant for Type Theory

JTrek - a real-time space combat simulator played via telnet session

Runs Professor Scott Aaronson's String Rewrite Systems that simulate the 3N+1 problem

GRT Framework (Java) version 7, robotics framework for the Gunn Robotics Team.