The new dose of Jackass is way dumber, grosser and gayer (there are more things shoved up male butts than a cowboy could dream of up on Brokeback Mountain, and the guys even sing a homo anthem from La Cage aux folles). Just don’t ask me to pin a rating to this painfully funny S&M party flick. If you get off on the idea of Johnny Knoxville, Bam Margera, Steve-O, Chris Pontius and the gang pulling a stallion’s throbbing penis out of a mare and then chugging down the horse jizz, only four will do. If you puke at the thought of watching the guys plucking their pubes and heinie hairs to make a beard for Ehren McGhehey to wear in a skit on Islamic terrorism, zero will seem too generous. For everybody, the recent death of Steve Irwin may cast a pall over the bit in which Steve-O sticks a fishhook in his cheek and uses himself as bait for sharks and other monsters of the deep. But the heart of Jackass — the adolescent drive to bash body and soul into the symbolic brick wall of maturity remains pure.