Illusion Labs, developer of the popular iPhone game Touchgrind, has posted a video demonstrating a Mac version of the game utilizing the multi-touch capabilities of the MacBook's trackpad.
http://www.youtube.com/watch?v=FsfROlawZoQ
The developer describes it as tech demo and hasn't committed to releasing it. Illusion Labs is the same developer who demoed their iPhone games on a large multi-touch table in 2009.
All of Apple's notebooks now contain a multi-touch trackpad that could be used for such purposes. In fact, Apple's multi-touch trackpads can track up to 11 distinct multi-touch presses.
Article Link: Multi-Touch Trackpad Gaming Demonstrated on MacBook