The iPhone platform now has more than 100,000 apps, and they're almost all available through the iTunes App Store. That's an amazing rate of growth, and it shows how rich the iPhone platform is for developers. Of course, this list can't possibly be comprehensive. If you're comfortable with having everyone know where you are at all times, go ahead and try those apps out, too. Here, though, are my first favorites.
Memorize the sequence of letters or numbers. The sequence will then be covered with bubbles. Pop the bubbles in the order of the sequence to beat the level.
8. Task Coach - This is the iPhone version of the open-source Task Coach desktop application. It features basic task editing and synchronization with its desktop counterpart over the network.