It was audience participation night Tuesday in the Wharton Center's Great Hall.

When piano rocker Ben Folds nodded, the crowd responded.

When he needed voices to fill the chorus, they sang.

When he paused to take a sip of water or empty his pockets (which held a wallet, papers and a cucumber), they called out requests.

He responded to shouts for classics, such as "One Angry Dwarf and 200 Solemn Faces" and "Eddie Walker." He knocked out a romantic rendition of George Michael's "Careless Whisper" when asked for it.

And, an improvised "porno" version of "Rock This Bitch" shook the request-hungry crowd.

"Folds takes one more step toward Vegas everyday," Folds said between porno sound effects.

The show was early in Folds' 15-city tour of college campuses, but showed more energy and familiarity than his Ann Arbor stop Saturday.

"I can't repeat the same jokes," Folds said, noting the returning members of the crowd.

There wasn't much repeating at all.

Although he stuck with a few live-show constants, including "Zak and Sara," "Army" and "There's Always Someone Cooler Than You," he pulled out fan favorites that aren't often pounded into the piano during his live sets.

"The Last Polka," a minor-key version of "Song for the Dumped" and a Nickelback-style rendition of "Brick," all drew cheers from the hyperactive, sold-out audience.

"If I'd played it this way, this song would have been a hit," Folds said of the throaty, bass-driven version of the Ben Folds Five radio-friendly track, "Brick."

But the audience couldn't get enough. They started off head-banging to Queen's "Bohemian Rhapsody" while they waited and ended with a showing of lighters and cell phones encouraging the pianist back on stage.

He reappeared for a three-song encore after more than 20 songs, ending in time to catch an early ride to Tulsa, Okla., for a Thursday show. When the tour ends in early May, Folds said he'll have to decide what's next: Release an EP to finish his set of three, or stick just with a full-length album.

"I got myself all in a titter over it," Folds told the crowd, testing new material, including a tribute to Elliott Smith and a Rent-A-Cop's tale of work woe. "I've been waffling. When I get back, I'll see if I can possibly get everything mixed in 10 days."