Switchball is going to be on Xbox Live Arcade this Wednesday and it superficially falls into the Mercury Meltdown/Super Monkey Ball/Marble Madness category. You guide a ball through a maze, but the twist is you can change the physical property of the ball. When you change it into metal you can slam into objects and changing it into air lets you float over traps. You also get online racing play for eight people for 800 Microsoft Points ($10).
Also out this week is Word Puzzle, essentially a modified word search game with bombs. It might be interesting, but I’m lost on how you “circle” words. I imagine something like that would work better with the DS. The other question I have is if Word Puzzle randomly generates grids. If it doesn’t I imagine online matches can get one-sided pretty fast. Like Switchball, Word Puzzle is 800 Microsoft Points ($10).