Like the Artist Formerly (and, after a brief respite, currently) known as Prince, the Enormous Room announces its existence with a symbol. You'll know you're in the right place when you see the silhouette of an elephant, affixed to a door in the general vicinity of Central Kitchen. Up one flight of stairs one discovers the Room itself, which looks like the upshot of a 'Trading Spaces' episode featuring Lou Reed's loft -- as envisioned by Ali Baba. Languid hipsters recline on ample pillows on a raised platform along the wall, while everything from acid jazz to R&B flows from the sound system, courtesy of a revolving roster of local DJs. In the mix for the future, according to chef/owner Gary Strack, is alternative entertainment ranging from performance art to play readings. Until then, the E.R. remains Central Square's closest contender to the upscale ambience of Bostonian hangs like Mantra and Red Fez, offering cocktails almost as generous as its square footage. --