UPDATE: Gas Panic in Roppongi closed in 2011. The Shibuya branch is still open, if you really must know.
Gas Panic is a Roppongi institution, where young people go to grope other young people. The chart classics and Eurobeat play at such high volume that your mating ritual needs to be physical rather than verbal. To give an idea of what it’s like, note that you must have a drink in your hand at all times, and drinking water is not in evidence. Every drink costs ¥400 at happy hour (6pm-9.30pm daily) and all night on Thursday. There are three other Gas Panic outfits in Roppongi, two in Shibuya and another in Yokohama; check the website for details.