Polybius is an arcade game that drives people insane.
An urban legend possibly inspired by rumors of an early version of Tempest that aggravated cases of photosensitive epilepsy and/or the real life arcade-based deaths of competitive gamers Jeff Dailey and Peter Burkowski (commemorated with all the proper respect in the Cracked article "6 People Who Died In Order To Prove A (Retarded) Point"), POLYBIUS was supposedly a controversial arcade game released in 1981.
The game was released by a German company called Sinnesloschen (German for "sense delete" or "sensory-extinguishing")). Some versions of the story say the game was released in Poland, some in Portland, Oregon. Most agree it was a Tempest-like vector graphics shooter that, when played, assaulted the player with confusion, memory lapses and suicidal thoughts via subliminal messages. Those that survived swore off video games for the rest of their lives.
The legend also involves it's own variation on the Men In Black theme, with mysterious researchers periodically showing up to collect data gathered by the machines.
POLYBIUS (the game) was named after an Ancient Greek historian born in Megalopolis, a town in the prefecture of Arcadia that we totally did not just make up. Most of his bibliography is lost, however; a pretty grim fate for a writer. We mostly know of his primary claim to fame secondhand.
His secondary claim to fame? Cryptography and Telegraphy. The creation and transmission of secret messages.