Yo, some ideas:
1. Chess game (I'm not up to this, but somebody else can do this one), and maybe with AI for the next level of this hahaha
2. Scrolling platformer, any kind of platformer, but scrolls, would make use of XO-CHIP features for smoother scrolls however
3. Nobody tried Tetris with standard rules here yet (and I'm not up to this)
4. Some sort of complex program that makes use of high level of abstractions, for this case, I'm go with raytracing.
5. Music program (I'll elaborate this later)
