With the iPhone App Store having now delivered three billion downloads, you might think every possible idea had already been thought up. You’d be wrong. Here’s our guide to some recent releases which, while not necessarily useful or desirable, are notable in some manner.

PocketHeat: As the billing has it, this turns your phone into a hand warmer by ratcheting up demands on the processor to force the handset to heat up. It’s reported that this app originally worked exactly as originally described, though this sounds very unlikely. In any case, it’s now clearly marketed as a novelty item with no real heating power. Still, you have to give the makers some credit for satire given recent reports of iPhones overheating.

Chomp: This is one of a growing number of apps designed to help you find apps. That may feel a little Synecdoche, New York for comfort, but Chomp has earned some good reviews as the most simple yet intuitive tool of its type. (For dedicated websites performing the same task, there’s one that has to be mentioned more for its creative domain name rather than its content: app.itize.us)

Food Watch New York: This is a simple mapping tool which displays which nearby restaurants have recently failed safety inspections. While that may sound useful, it could have some drawbacks: if you eat regularly in an area, there’s a risk that using it will bring up an establishment you’ve already visited…

MyFace: Offering personalized cosmetics tips based on your ethnicity, skin tone and skin color, this is notable mainly for the fact that my mother can now no longer get her social networks confused and ask people “Do you have a MyFace?”

SecurityCam: This sets your iPhone to take a picture either at regular intervals, when it detects a sound, or both. It’s probably not going to be in the CIA budget, but should be a hit with creepy younger brothers everywhere.

iHome + Sleep: Have you ever thought it would be neat to be able to press one button on your phone the moment you wake up and have your it automatically post on Facebook and Twitter to let people know you are awake? No? Probably OK to skip this one then.

forChan: This app has already been pulled but is a great example of the tricks developers are using to get round Apple’s terms and conditions. It’s an app designed for looking at pictures of dogs from a message board. And if users decide to change the easily customizable settings so that the picture come from a pornography board instead, well the developers can’t be blamed for that, can they? This was approved and operational in under 12 hours, and then removed not much later thanks to the secret bonus level of the approval process (that being media scrutiny). Incidentally, if you do want to look at pictures of naked ladies, there’s a very useful free app named Safari.

Disney World Wait Times: This does exactly what you’d imagine, with the bonus that users can easily update it with their actual experiences to make sure the figures are as accurate as possible at any precise moment. This can only be a forerunner to the “Are We Nearly There Yet?” app.

Gunman: This is a remarkably simple idea which could prove effective. Your screen acts as a traditional viewfinder but with a target scope. You set up a multiplayer game via WiFi and take a picture of your opponents so that the app can recognize the color they are wearing. And then the game begins.