Dance is a universal language with infinite variations, its rhythms and beats giving us license to sway, swing, twirl, dip, stomp and otherwise move across a floor to the sounds spun by DJs or played by musicians of every genre. But it's not just about the music. It's also about the building, the decor, the lights, the acoustics and the people. It's about state-of-the-art sound systems, such as those at Beta Nightclub and The Black Box, and it's about a wide range of music styles to appeal to a diverse audience; Milk is just one example. When it's time to take a break from the moves, it's nice to have a space where dancers can relax and chat, spaces such as the rooftop at Club Vinyl and Your Mom's House at Pearl's. If you don't already know how to dance swing or salsa or groove to the blues, you're in luck. Several of the top dance venues in town, including the Grizzly Rose and La Rumba, offer free or nearly free lessons, followed by the chance to try out your stellar moves with old and new friends.