We’ve seen motion sensing in portable games before. Yoshi’s Topsy Turvy and Wario Ware Twisted both had motion sensing carts, but there haven’t been any games like that for the DS. Since accelerometers are all the rage there’s a project with said carts in development. The cart is a nifty idea, but only homebrew games like Sprout DS where you rotate the system to turn around support the cart. When the cart is finally released there will probably be better apps, maybe even full blown games designed with the accessory.
Thanks for the top Ken!