While I was working at Cipher Prime, we were contracted by Leap Motion to develop a game for their gumstick-sized motion controller. We knew that most other teams were developing single-player experiences to be played with both hands, so we decided to make a game that would showcase the Leap's options for multi-user experiences. However, we also found that the space was often not large enough for two players to perform complex, accurate hand motions, so we needed something that would control very simply.
Shimsham is a relatively simple concept: it's a head-vs-head game, where both players have their avatar (a ball) and several boxes under their control. The goal is to have one of your boxes hit the other player's avatar. The complicated bit is that gravity is not the same for both players: they control gravity only for their avatar and boxes. This allows for very technical (if not a little vomit-inducing) play.