I read about this today on Crispy Gamer. Is anyone familiar with this urban legend? This is pretty creepy (although almost certainly not true)
The urban legend goes as such: in the 80s, an arcade game called Polybius appeared in the suburbs of Portland Oregon. It had a pretty nondescript cabinet, and gameplay which was similar to Tempest.
People who played the game suffered from side effects such as memory loss, nausea, terrible nightmares, and epileptic fits.
Men in black coats came in every so often to record data from the machine.
A month later, the game was gone.
Some people claim to have a ROM of the game, and a few fuzzy shots of the cabinet exist, as well as a screenshot of the title screen.
More info here:
http://www.freewebs.com/polybiustheory/I get a kick out of urban legends like this. Wasn't sure how common this one was.