Tucked away in Potrero Hill (but easily accessible by bus), Metronome offers pretty much anything you could want in the way of rug-cutting. It'll set you up with lessons ranging from beginning group Argentine tango to one-on-one ballet instruction, from massage for dancers to lessons on becoming a dance instructor. Some classes are focused on fitness; others (like the ballroom dancing program) can prepare you for serious competition. Metronome offers a men-only beginning hip hop class for boys who'd like a safe space in which to explore their inner freak, and there's even a wedding workshop for couples looking to share a perfect first dance. You can pay for classes in 10-lesson blocks or on a drop-in basis.