If you have an iThing but you've not yet tried Chair's excellent battle 'em up Infinity Blade, then now is definitely the time to do so. It's half price for the time being, which is turbo-awesome because Epic Games said it would never lower it!
You can pick it up for $2.99 in the US and £1.79/€2.39 in the European territories.
As well as the price slash, Chair has stated (at a GDC panel that I wish I could've attended) that the game's next update is coming very, very soon. This should be the long-awaited major patch that includes an all-new dungeon area, enemy creatures that are more powerful than the God King, and competitive multiplayer.
Infinity Blade is one of my favorite games of last year, and that's including console titles. Seriously, get it if you've not done so yet!