Laugh all you want, jocks—us geeks know where it's at: text gaming. Bringing virtually every text-based game you've ever heard of to the iPhone gives the genre a whole new lease on life, and you the most prodigious time-waster imaginable.
Never played a text-based game? There's a learning curve, but don't be put off. I was still traipsing around in floral overalls (thanks Mom) when text games were dying, yet I've had more fun playing Zork on my iPod than just about any high-budget 3D game.
From the App Developers: Frotz lets you download and play free works of Interactive Fiction (a.k.a. text adventure games) on your iPhone or iPod Touch.
Frotz plays games written in the Z-Machine format. This format was invented by Infocom and was used to produce classic text adventures from the 80s such as the Zork Trilogy, Hitchhiker's Guide to the Galaxy, and Trinity.