"More than any other rock musician, he is the baddest [expletive] in the world." So declares Dave Grohl in the trailer for "Lemmy," a rockumentary about Lemmy Kilmeister (above, center) , the wart-faced, gnarly teethed and purportedly mega-sexed frontman of the pioneering British metal band Motörhead. A hit at the South by Southwest Film Festival, the movie is making its way across the country for one-night stands -- just as Lemmy himself has done for decades (he and the boys will be at First Avenue again Feb. 15). Not available for preview, it promises many more testimonials on his bad-assedness from the likes of Alice Cooper, Slash, Mick Jones and Billy Bob Thornton. But it also offers a behind-the-scenes look at the guy who, from all accounts, hasn't changed his look, lifestyle or attitude since he first entered the rock 'n' roll world as a roadie for Jimi Hendrix. The filmmakers spent two years with Kilmeister, capturing him at home with his son and his huge collection of World War II memorabilia and on the road with his tight-knit band and crew. Sounds both sweet and sordid. (11:30 p.m. Sat., Riverview Theater, 3800 42nd Av. S., Mpls. $8. RiverviewTheater.com.)CHRIS RIEMENSCHNEIDER