How do you know when you've thrown a great holiday party? When your guests have such a good time that they ask if they can come back the following year.

That pretty much describes the atmosphere at the Sleighriders annual benefit concert, which will mark its 25th anniversary Monday night at Shank Hall. Doors open at 7 p.m. and the admission is a donation of $10.

"Every year, we have new people come in to play with us," said Xeno, the longtime Bad Boy guitarist and one of the event organizers. "Every year, they call back and say 'I want to do it again.'"

The 2007 Sleighriders lineup features newcomer Greg Koch, along with regular attendees like Cheap Trick drummer Bun E. Carlos, Streetlife sax man Warren Wiegratz, former BoDeans bass player Bob Griffin, Eddie Butts, Sigmund Snopek, harmonica wizard Steve Cohen, Scott Finch, Joe Hite of The Boogiemen, Tommy Greywolf and Rachel Trapp from No Strings Attached, Char Fiore, Tony Brice, Jay Bartholomew, the Speakeasy horns and others.

"It's the usual suspects," said Steve Grimm, Xeno's partner in Bad Boy. "I don't know if there is another place where you can see that kind of talent under one roof. It always blows my mind."

Proceeds from the show and auction benefit for the SafeZone Community Arts Center. "SafeZone is an organization that offers free lessons, instruction and instruments to needy North Side kids," Grimm said. "It's kind of at the heart of what we did when we were kids. We were wayward kids who needed that kind of help."

The vibe at the Sleighriders show is always festive. Because it's rare for so many local musicians to be in the same place, it has the feel of a class reunion mixed with an all-star game.

The performing lineup changes throughout the night and the set list features Christmas standards mixed in with an array of rock, soul and blues songs delivered in a "wall of sound" fashion. Solos are impressive, but generally not excessive, and the players seem to be having as much fun as the dancing spectators.

Xeno serves as the unofficial music director, but gets help charting songs for violins and horns. "There are a lot of bandleaders there," he said, referring to a group with more than 1,000 combined years of performing experience. "It's not that hard."

The hard part is taking care of other logistical elements, like making sure everyone has the date clear, providing catering for the Sunday rehearsal and the show and keeping track of equipment for more than 30 performers.

"It's really time-consuming," Xeno said. "I ask myself every year, 'Why am I spending all this time all this effort? Then, we do the show and I say, 'Oh, now I remember.' It's always a great night."

Grimm agreed, and added a prediction.

"We're going to tear the roof off the sucker," he said.