Sure it's completely useless, but it's damn cool.

It's the new iPhone app from Zippo that turns your phone into a virtual lighter. Pick your lighter style, then flip open the cover, and flick the wheel to "light" it, just like on an actual Zippo. Turn the iPhone and the flame follows. A flick of your wrist snaps the cover shut.

Again, not useful for anything, except maybe satisfying pyros' urges without buildings burning to the ground. Here's their video that shows what the app can do.