Howdy!
Unity 3D has announced that going forward all their mobile development licensees will be free (these have retailed for years at $400/pop occasionally having a free period).
This game engine was used to develop some very popular games of late (http://unity3d.com/gallery/made-with-unity/game-list) including Blood and Glory, Jelly Defence, ShadowGun, Battleheart and Muffin
