Google developers shocased a tennis game, in which a player should maintain a rally simply by using head movements to mimic racket movements. In another game, the Glass wearer needs to keep an imaginary pile of books perfectly balanced on his or her head.
Shape Splitter is a game where the player should swing or "slice" his/her hands in order to cut shapes that appear on the device's screen in half.
A video demo is available here.
Google Glass is expected to be generally available later this year.