MochiBits' SwipeTapTap is a surprisingly engrossing game despite its utter simplicity. Following on-screen prompts involving (what else?) swipes, taps and various combinations as quickly and accurately as possible is one of those things I'd never have expected to keep me entertained for very long, but it does just that. Not only that, it keeps things from getting stale by including a total of four game modes. And it's free at the moment, did I forget to mention that? Nah, I'm pretty sure I did.
Each of the four modes uses the same basic mechanics in different ways. Classic is all about inputting the correct gestures as they scroll across the screen in a timely manner. Take too long or screw up too often and they'll fill the screen and it's Game Over. Memory is more like a classic game of Simon, only with a touch screen interface. Speed is a race against time, requiring almost super-human-like reflexes at the higher difficulties. Finally, Endurance is one big continuous level with no end in sight and steadily increasing speed. Losing isn't so much a question of "if" but of "when."
And yes, for a limited time (in conjunction with "OpenFeint's Free Game of the Day") this finger-flexing homage to Simon is completely and totally free. All of the games modes. No money down. Zero dollars. There's absolutely no legitimate reason not to check it out.