Here's a way to give yourself a mild headache with maybe a touch of nausea, if you're into that sort of thing. This is what it looks to be strapped to the head of a drill. Fair warning: After 2:10, this may or may not be safe for work, depending on how your eyes are doing by that point.

[vimeo http://www.vimeo.com/12112625 w=500&h=284]

Who comes up with this stuff? Seeing in circles from Oscar Lhermitte on Vimeo. Hat tip: Geekologie