I was reading an article about The Clapper (the device that allows you to plug things into it and then clap to turn them on/off). In the article, the author mentions an iphone app that works the same way, where you can clap to turn on a light on your iphone simply by clapping.

Does anyone know which app this is?

I couldn't find anything in the App Store. Doesn't mean it isn't there, of course.

I don't know how useful it would be, since the app would have to be open to hear the clap. Though I suppose you could turn the lAuto-Lock to never and leave the iPhone plugged in.

On the other hand I have a Flashlight app on my iPhone. If I don't want to fumble around trying to find the app I can tap and hold the home button for Siri, and say Open Flashlight. Wa la, light.