3d Snake and 3d Tetris
http://www.youtube.com/watch?v=dhqusv6BNik
http://www.youtube.com/watch?v=F-D59joMqdo
They call their LED array a 'Cubix' but it's just an old LED project you can find info on here here and a step by step at Indestructables.com of a cheapo 4x4x4 LED cube here.
3D Snake on a 10x10x10 LED cube controlled with a WiiMote. The game is a classic. Eat the points, your snake grows, don't eat yourself. The use of the wiimote seems to go into every homemade project these days though. But you can't fault this one by watching it. Looks fairly playable.
The 3D Tetris isn't really like I'd want it. It's like laying down Tetris blocks as if they were sheets of paper when I want the old game Blockout.