I have almost no apps in my iPhone, only the most useful ones for NYC. But iSteam, a steam simulator, looks like a fun one to install and keep.
As you can see in the video, the application adds ultra-realistic steam to your screen when you blow on the microphone.
After that you can use your fingers to clean it, causing squeaky sounds, condensation, and drops that get affected by the orientation of the phone, like it would happen in real life. But without frying your iPhone. It's silly. It's useless. It was a must get when it was free. Now that it is $0.99, I'd think about it.
Kostas Eleftheriou-one of the guys who does the app-says that iSteam will be free until the weekend, but there has been a problem with Apple's iTunes App store backoffice software. I still see it as $0.99, but some people are reporting is back to free. [iSteam]