HexRacer is a 3D multiplayer racing game with a unique "painting" dynamic. As you drive, you can opt to lay down paint in your team's colour; painting will slow you down, but anyone on your team will travel faster on the paint in the future. Depending on settings, you may also be able to erase other teams' paint (also at a speed penalty).
HexRacer was written in a team of three people for CPSC 585, the game programming course at U of C. My contributions to it involved the networking, AI, event system, and most of the physics and 2D rendering (3D rendering and effects were done by Alfred). The code was written in C++ with the help of a few libraries: SDL, Qt, OpenGL (and GLU and GLEW), Bullet physics, Boost, and OpenAL. There are about 45,000 lines of code.
There is a video of the gameplay on YouTube.
There is an image gallery with some HexRacer screenshots.