Today is the perfect day to add to your collection of casual iPhone and iPod touch games thanks to three different developers’ willingness to make their games available for free for a very limited amount of time.

Kapowie ($.99 -> Free): A relatively new and fast-paced tap-shooter that claims to be one of, if not the only game with penguins in elevators.  The game will have you tapping targets at a rapid pace in order to meet a specific quota within a limited amount of time.  It features seven levels with difficulty levels that ramp up as you progress, and global leader boards to see how you compare against the rest of the world.

World of Tunes ($2.99 -> Free): An oddly adorable rhythm game by the developers of Homerun Battle 3D.  In the game you must tap the Tuneys to the rhythm of the beat to obtain the highest score.  The game features 14 tracks, four game modes, and four boss battles.

StickSiege ($.99 -> Free): Another fairly new game that features stick figure characters and touch-based controls.  In the game you will be tasked with defending your castle by firing arrows at the oncoming enemies.  Ground soldiers aid you in your battle, and you can upgrade their armor and weaponry along with your own with the gold that you earn.  The controls can take a moment to get used to, as there is a lot of timing involved, but you should have it mastered in no time.  The game also features OpenFeint connectivity.

You must hurry up and download these three games while you have the chance, because they won’t be free for very long.