From swing to salsa, dance crazes come and go with an almost Swiss precision. (We're still awaiting the return of the Freddy.) At the advance of each new wave, the Mercury Cafe is ready, opening its funky doors to dancers of all persuasions. While swing and lindy hop are still going strong, tango currently reigns supreme in Marilyn Megenity's luscious eatery/bar/cabaret on California Street, with weekly milongas, classes for dancers of all levels (from beginners to very advanced) and the occasional opportunity to learn from a visiting Argentine master. The Merc still shines brightly in the firmament of local nightlife.