WATERVILLE - There's a big crowd at Hafford Saloon. It's Friday night, and the place is packed. Folks are there, presumably, for the music and the drinks and, maybe, the mechanical bull that's gyrating in one corner.

But at 10:30 all eyes are on the stage, where Sandy Knight jumps and writhes and, sliding forward, plays all the riffs to a classic rock song with what looks, to the untrained eye, like practiced precision.

Except you can't tell if she's hitting the notes. She's not holding a guitar, or anything else, in her hands. She's not playing music at all. But she is competing in Week 7 of Maine's Air Guitar competition, vying for a place at the regionals in Boston later on this spring.

"She's going to be good," muses spectator Kevin Miller, after watching her take the stage a few seconds. "But I feel humiliated for half of them."

Sound absurd to you?

Olli Rantala, the executive director of the World Championships - held in Oulu, Finland - freely admits it might strike some as odd. "The once so absurd ... idea has bloomed into an international media event," he writes, explaining how the championships got their start in 1996.

This year, for the first time ever, Maine's holding a statewide competition, organized by morning show DJs J. and Jenay, of Skowhegan-based radio station Mix 107.9. Every Friday night for 10 weeks, contestants are gathering at Hafford's to compete, culminating with an air-off among the 10 finalists on May 2. (There are two weeks of regular competition left, if you're interested.) The winner gets a trip down to Boston to compete in the regionals. And the winner of that competition goes to nationals, held in an as-yet-undisclosed location later on this year.

Even though Maine didn't run an official competition last year, Portlander Erin McNally won the Boston regionals. McNally, who goes by the stage name "McNallica," was judging contestants on that recent Friday at Hafford's. The best ones - the ones who make it to nationals - go all out, really own their performance, she says, suggesting a trip to YouTube or www.usairguitar.com for a gander.

In one, 2007 Nationals winner William Ocean tears off his clothes, revealing a spangly blue suit-thing underneath, and then knee-jumps across the stage, exuberant.

In another, Hot Lixx Hulahan (http://www.thelovesongs.com/craig/airguitar/), who won the nationals in 2006, owns the stage, in what appears to be either a mariachi or pirate hat, doing something incredible that's rather impossible to describe.

Good air guitar goes beyond emulating rock star heroes to something all its own - different, fascinating and awesome - with a big twist of the absurd.

The sport isn't that weird, says McNally. "Everyone has done air guitar before. I mean, I've even seen air flute," she says, before heading over to her judging station.

Yes, but not everyone gets up on stage and attempts to, as McNallica puts it, "melt faces."

Maine's competitive air guitarists take it with varying levels of seriousness.

Alan "Axl Baby" Rose, 22, of Oakland, plans to wing it in the radio station's May 2 Air-Off. "I figure if I wing it, it'll be a lot better," he says. "If you practice, you'll be too nervous - that's when all (bleep) breaks loose."

Though he plays real guitar, and has air-guitared in private for much of his life, Rose is new to the cutthroat sport of competitive air guitar, he says.

Same goes for Sandy Knight, 48, of Embden. Knight, however, has been approaching the finals with a bit more forethought. She's been practicing at home.

"It's just second nature to me," she says. "Or maybe it's first nature."

Like many other air guitarists, she says she's not quite sure what draws her in. "It's something I never thought I'd be doing," she says, huddled at a relatively quiet table a few minutes after her performance. "I don't feel like I look like a fool. I'm having fun. I like the challenge. ... And I like to dance. Air guitar is kind of like dancing with a guitar."

Knight will be competing in the Air-Off, as will Kristen Theriault, 22, of Hartland. She decided to enter the Waterville competition on a whim, after hearing about it on the radio during a lunch break. "On the spur of the moment, I said 'Let's go do it,'" she recalls. "I like music, but I never thought of myself doing air guitar before."

She thought up some moves before the big night, she says. "I was pretty nervous. Before I actually did it, I got on YouTube and looked up 'air guitar.' I found this guy who was in Worlds a couple years in a row - I call him the 'tiger sweatshirt guy.' He was a riot. So I kinda watched him a couple times and got some ideas."

Exactly how does one judge the talents of a guitarist playing without an actual guitar?

Officially, there are rules and judging criteria.

Scoring is done on an Olympic Figure Skating scale - from 4.0 to 6.0 - based on three criteria: technical merit, stage presence and "airness," according to U.S. Air Guitar's Web site.

"When air guitar is good, when it transcends and achieves what is known as 'airness,' you forget for a moment that what you are watching is a person flailing about, playing an invisible instrument, and they become a conduit through which the music passes," writes Dan Crane, in an e-mail. "In broader terms, it's like sculpture - air guitar is all about negative space."

Crane came in 8th in the Worlds in 2006. A freelance writer, he is famous (in some circles) for his starring role in the aptly named film "Air Guitar Nation" and for his memoir "To Air Is Human: One Man's Quest to Become the World's Greatest Air Guitarist."

With the stage name "Bjorn Turoque" (pronounced: too-ROCK), Crane signed up for his first competition because "it sounded ridiculous and stupid, and exactly the kind of thing I'm drawn to," he writes.

But that combination of tongue-in-cheek silliness and determined focus seems to be part of the temperament of the competitive air guitarist.

Air guitarists, says McNally, know just how absurd their pursuit really is - but that doesn't stop them from approaching the competition with the utmost gravity.

On this Friday night, McNally flatly refuses to perform. She won't even show some moves. She's just here to judge. "We are in the beginning of air guitar season," she says. "I'll take every edge I can get. If one of those edges is keeping my moves on lock, I'm going to do it."

While most of the relatively "green" Waterville air guitarists prepare little, if at all, for their gigs, McNally does hand exercises, practices her fretwork and brought an "entourage" with her to last year's US Air Guitar Championships in New York.

In the hours before the performance, she says, "all hands were on deck. It was a fury of hair, makeup and hair spray."

She got fourth place overall, and was subsequently described in a USAG press release as the "upstart ingenue ... who impressed enough to earn a perfect score of 6.0 from Malcolm Gladwell: the best-selling author, renowned social critic and (featured at the top of his resume, no doubt) US Air Guitar judge."

McNally, however, has her own list of good-air-guitar criteria. "Showing up. Rocking. Slaying. Owning it. And then leaving," she says.