An improved version of the game Beatmania.
(Also known as: IIDX)
A 7 keys and turntable game made by Konami, the same people who brought us Dance Dance Revolution. It is far more challenging, harder to find, and has better songs than DDR. Most of the people that I've seen play at my local arcade are pretty skilled, and aren't fat Wapanese bastards.
You don't believe me when I say IIDX's music is better? Go listen to the song "thunder," which is from that game.