Remember Christopher Reeve’s blow controlled wheel chair? [Shwetak] sent in his blowable computer interface. It doesn’t require anything but an on-board microphone and a decent set of lungs. It works by taking audio fingerprints to determine the location on the screen that you’re exhaling on. The demo video (avi) shows off some surprisingly accurate location detection. You can get a few more details from his research paper. (If you need a decent avi video player, check out VLC player.)