I'm not responsiblefor any ill-effects resulting from this.
dogfeathers.com/java/spirals.html
Stare at the spirally thing for a minute (sit about half a metre back), then look at your hand.
For me it worked better in reverse, but you might find otherwise.
(edit: If you're running some sort of Unix, hp.vector.co.jp/authors/VA004959/gru/gru-8087.tar.gz does the same thing much more effectively (compile it yourself or if you're running FreeBSD get it from ports/games/gru).
(,
Sat 1 Jun 2002, 17:39,
archived)
dogfeathers.com/java/spirals.html
Stare at the spirally thing for a minute (sit about half a metre back), then look at your hand.
For me it worked better in reverse, but you might find otherwise.
(edit: If you're running some sort of Unix, hp.vector.co.jp/authors/VA004959/gru/gru-8087.tar.gz does the same thing much more effectively (compile it yourself or if you're running FreeBSD get it from ports/games/gru).