Here’s a good opportunity to see Cocos2D iPhone gaming framework in action.

Punchball is an original 2D arcade boxing game for iPhone. Technically the two most interesting features are a bit unconventional physics simulation, leveraging Chimpunk engine and peer-to-peer multiplayer gaming via Bluetooth, which is simple on the surface, but in practice requires all kinds of tricks for latency compensation.

You can get Punchball sources from GitHub and compile it yourself, or install it directly from AppStore.