So, I loved Tris on the App store, and was saddened when they took it away because the paid offical EA version really sucked. I got excited when I got my droid because I figured, open source, something like Tris could exist. Enter Tetrads. I love this app. It plays just like Tetris, and works well controll wise on my Eris. I don't know why this is such a simple game, but I never get old of it... If you're a fan, try it out.