iPhone app development (2)

I have some more application development idea for iPhone platform.

1. Language learning application, especially Mandarin.
The target customers are people who are learning Chinese.

2. A social game, with everyone can place some trap, or throw bomb.

3. A drifting bottle application, where you can place throw your drifting bottle into the sea, and the server will track down where the drifting bottle goes.  You may also choose to scan and pickup other person's drifting bottle.