This place maintains its "hot" status. First you have to find it, and then you have to convince the bouncer to let you in. So here's what you need to know: Look for the mattress shop south of Dupont Circle, then look up. "ESL" (as those in the know call it) sits above the shop, and hangs only a tiny plaque at street level to advertise its existence. Wear something exotic and sexy. If you pass inspection, you may be surprised to find yourself in a restored mansion (Teddy Roosevelt once lived here) with fireplaces, high ceilings, and a deck out back. Or maybe you'll just get right out there on the hardwood floors to dance to acid jazz, hip-hop, reggae, or Latin jazz tunes spun by a deejay.