I'm working on a large program based of the flash game "trapped". Its prety big (13979 bytes!) but it does work on both the ti83 and the ti84. Of course it runs faster on the ti84.
It uses xLib to get great graphics. It has 25 different rooms, each with a unique puzzle. over 30 interactive elements. Enemies, items, and a Boss at the end of the game. The graphics are great, and it runs pretty fast. The game is not available for download yet, because i am still bug testing it. But stay posted!