Make realtime multiplayer games using cocos2D | (I+D)+(i+c): Gamification, Game-Based Learning (GBL) | Scoop.it
Cocos2D is a popular open source framework for building iPhone games. Its quite powerful and can be used to develop a wide range of 2D games. Here is a list of some of the apps on the appstore developed using Cocos2D.

Via Vincent Demay