I'd love to try this one out, but my Mac ain't a laptop. MacSaber takes advantage of the motion sensor in newer Mac laptops (it's not yet compatible with older ones). It senses the speed and acceleration of motion as you swing your laptop around, producing varying lightsaber sounds (of both movement and striking). The site also mentions keyboard backlight effects, and invites you to try it out in a dark room, so apparently the app not only sounds cool, but looks sweet, too.