I’ve mentioned the excellent Cocos2D open source 2d iphone game engine many times. The engine itself comes with many examples of the different features available, but something that comes up frequently is that people want some example games to look at it. Here are 5 terrific examples.
1) Gorillas – I’ve mentioned this game before, it’s a great example of a "Worms" type game, and has been around on many different platforms.
2) ABC 123 – A sequence memorization game. This game is really cool, letters appear, and you have to memorize the correct sequence by destroying bubbles that pop up.
3) TweeJump – This is a very nice platform jumping game. You jump from one platform to the next, if you remember the game Icy Toweres, this is similar.
4) Thrown – A Physics puzzler, not the best graphics, but an excellent coding example for Cocos2D that also utilizes the Chipmunk physics engine.
5) Grabbed – A dragging game example from the same author that created Thrown, and also utilizes Chipmunk.
Sapus Media, who started the Cocos2D iPhone project has an extensive source code example which is of their app "Sapus Tongue" you can check it out here, it’s not free, but these guys have put in so much into Cocos2D that I mention it here.
The book iPhone Cool Projects contains an example of a minigolf game that was created in Cocos2D.
And of course you can find the Cocos2D iPhone google code project itself here.