Wolfenstine RPG is pretty fun to play.

Around me is a great app to find anything from a restroom to a autopart store. Gives you directions, email addresses and a number.

AirMouse is another fun app that lets you turn your iPhone/iTouch into a airmouse over a WiFi connection.

Also jail breaking it and adding Cyorder to record video and such is always neat.
To live is to let die