It's hard to imagine that an anarchic roots-rock band like NRBQ could sell out a 7,000-seat theater, but that's just what the New York State quartet did at Wolf Trap last night. NRBQ could be the next Bonnie Raitt -- emerging from 20 years of roots-rock cultdom into mainstream success. No one deserves it more, for no other act better captures the carefree humor and spontaneity of rock-and-roll.

NRBQ has often been called "the world's best bar band," and they turned Wolf Trap into the world's largest bar. The crowd was on its feet most of the night, dancing and balancing paper beer cups, and the sound mix went in and out of focus -- just as in a bar.

Terry Adams was both keyboardist and emcee as he stalked the stage barking out introductions like a cross between Groucho Marx and Sun Ra. Adams called out whatever tune struck his fancy at the moment -- everything from Johnny Cash's "Get Rhythm" to the band's own "Howard Johnson's Got His Ho-Jo Working." The band did four acoustic numbers (with Joey Spampinato strumming a mandolin and crooning "Mona"), but the highlights were the flat-out rockers like "Wild Weekend" and "Ain't It All Right," which Al Anderson pushed into overdrive with his manic guitar.

Detroit pop-rocker Marshall Crenshaw is a much better songwriter than singer, yet he devoted a large chunk of his opening set to songs by John Hiatt, Bobby Fuller, Pete Townshend and Richard Thompson. This was a dubious strategy, for Crenshaw's pinched standoffish vocals couldn't improve on the original versions, and these songs took the place of some gem-like Crenshaw compositions. This was a better-than-average Crenshaw show nonetheless, for guest drummer Kenny Aranoff upped the energy level on every number; Aranoff did a great Keith Moon impersonation on "I Can See for Miles and Miles."