Most chellenging for me contest on igdc.ru (former code.rpro.ru). The goal was to create racing game in 128Kib with NO external resources. I was enought with little less then 56k. No sound was used. Textures and car's meshes was packed in code with constant arrays of pixels and vertexes. Road was generated radomly on each race.
Writen in Delphi 7, pure WinAPI and pure OpenGL API. EXE packed with UPX.