Get Your Foldblaster 5000zx
http://www.metafilter.com/mefi/35883
Powered by… yourself. Watch this, then grab a t-shirt and try it out! Let me know how life-changing it was.
Update (28-MAY-2006): There used to be a longer video with more examples (including one you could do while standing) here: http://www.metafilter.com/mefi/30080 but it appears the link is down. Anyone got an updated link? Lemme know!
Update (13-APR-2007): Finally, it’s back! Thanks, Bryan.