Today only(13 June 2011), Palladium Power is making their Windows Phone game Orb free for all Windows Phone users. The game has recently been updated to v2.0 and the makers want you to try it out. The description for Orb reads:
ORB is a fast-paced 2D action game requiring skill to keep your rolling ball on solid tiles and to not fall down. Use fans to jump across large gaps and boost fields to get the full thrill. But take care to not run into dangerous mines or getting pushed into a hole by a slider. Compete with others at the global Online Highscore!
Their game is normally $1.29 and includes a free trial, but if you are looking to add another excellent game to your Windows Phone game library, head on over to the Windows Phone Marketplace and search for “Orb” or search on your Windows Phone.