What will they think of next?

The range of apps in the 15,000 available on iTunes is astonishing. I've covered Ocarina, a 99-cent let's you play your iPhone like a flute. Who would have thought it? And of course, one of the best-selling apps of all time is the 99-cent Koi Pond, which makes it look like you have fish swimming around inside your phone.

Other off-beat apps include the $1.99 iBeer, which appears as if you're drinking a beer (see a video of it on YouTube) and iFog (99 cents) and iFog Deluxe (free), which make it appear that your screen is fogged up when you blow on it.. You can write on it, rub it off, and e-mail your "foggy" from within the applcation. (See it on YouTube.) Another clever app recently released, iSpectrum Color Blind Assistant, is for those who are color blind. If you're in a situation where you need to identify a color, you can use the camera to take a photo, then touch the area of the photo to see which of 500 hues you are looking at.