On a recent Friday evening, déjà vu sets in. It's not because Ben Kweller is on stage doing his best Bob Dylan for the fans. It's where Kweller is doing his thing that feels so familiar. It's like a mini-Crystal Ballroom up in here: comfortable bar service. Sky-high ceilings. Over-21 upstairs mezzanine. Hordes of young 'uns all over the place. Most of us have never been here before, but it feels like I've been here a million times.

That's the spooky feeling behind the latest nightlife haven to open up on the lower eastside: the Bossanova Ballroom (722 E Burnside St., 233-7855). Welcome, you kick-ass new venue, you. Where have you been all my life?

Bossanova's appeal starts with its location. It sits above lower East Burnside Street (in the former shell of the Viscount Ballroom), blocks from the soon-to-open Jupiter Hotel and a short walk from the tasty, vegetarian-friendly treats of the Farm Cafe. That Bossanova feels familiar is no real surprise, either. It opened in August under the helm of the scenemakers behind the Shanghai Tunnel, Bar of the Gods, Tiny's Coffee and Genies Cafe.

Bossanova isn't always about the rock. Most weekdays, the place swarms with salsa, swing and tango instructors and dancers doing their thing. This ballroom, first built and used as a Masons Lodge in 1907, was made for dancing. Philip Ragaway, Bossanova's main helmsman, agrees. Ragaway says he wanted to extend some "carry-over goodwill" of the Viscount Ballroom--the former home to a portion of this town's dance community. Besides, says the jovial, common-sensical Ragaway, "it seemed like a good thing to do with my Monday, Tuesday and Wednesday nights."

When Ragaway and company moved in, they revamped the setting, sexing up the bathrooms and the upstairs lounge and inviting those groups right back in. In addition to the Lindy-hoppers and East Coast swingers, Ragaway says, there's a certain posse of swing and salsa voyeurs who like to spy on the dance floor from the comfortable booths upstairs, with cocktails in hand.

Whatever its merits--dance hall, rock venue, billiards room (there are five tables upstairs)--it seems Bossanova is destined for success. By Ragaway's watch, this zone between the Burnside Bridge and Sandy Boulevard is on a course to overtake Old Town as Portland's entertainment district within 10 years.

Good thing, says the veteran nightlife mogul whose bar Shanghai Tunnel sits in the midst of the current zone, "because I'll need someplace to put my stuff."