Game Dev Story is a fantastically addictive game from Japanese developer Kairopark that has run you own mini Activision, Electronic Arts, Ubisoft.
The game drops you into a startup studio that you get to name and has you make the calls on what to develop, who to hire, what to research, what to ship, what to can. It's a surprisingly deep game that runs on the iPhone, iPod and iPad.
Here's a look at the $5 game in action on my iPad. I'm sort of in love with all of the inside jokes.