Contrary to popular belief, rock and roll is not a form of music. It's not an attitude, either, or a lifestyle, or a sexual position, or even a catchphrase. It's an accident. Literally, an accident: a collision of bodies, a random act of gross negligence, a forced release of bodily fluids. As such, a rock show should always have an element of surprise, of danger, even. Take, for instance, the Risk (who will perform Friday, September 12, at the Climax Lounge): Rock and roll is the only term besides "disaster waiting to happen" that aptly describes this fearless foursome. Bassist Nick Anderson and singer/guitarist Joaquin Liebert started playing together in the mid-'90s as members of the mod/ska/soul combo the Redemptions -- who failed to find much of an audience among Denver's ska scene simply because they weren't quite sure how to suck. The two wound up playing with each other a few years later in Hi Fidelity, along with guitarist Nathan Marcy (also of Yellow Second) and drummer Greg Wildermuth. After releasing the disc Adventures on Planet Heartbreak in 2001, the band changed its name to the Risk; it's been nothing but sweat, broken bottles and brain-curdling screams ever since. Liebert can pack a whole stadium's worth of Bruce Springsteen's live energy onto a ten-foot-square stage; between all the leaping and pirouetting and dropping to his knees and crawling on the floor, he must go through more pairs of trousers than James Brown. And the music? Pure, soulful pop bashed out with all the fat-lipped abandon of Cheap Trick, the Replacements and the Clash. But as you're standing outside the club fishing around in your wallet for the five-buck cover charge and the phone number of some girl or guy you might be able to con into coming down and buying you a few drinks, remember this: Enter at your own risk.