Playing in a band isn’t always about sex, drugs and rock ‘n’ roll — take The Uncommon Houseflies for example. Substitute “hoping to score” for sex and “bacon” for drugs, and you get the idea. The rock ‘n’ roll, however, remains. At Friday night’s show at The Rud (422 W. Oak St., $3, 10 p.m.), the band will try out new material from their forthcoming album Excrement Weather, which is a follow-up to 2007’s Zombie Clowns Ate Your Sister’s Kitty. If you’re wondering if these guys have chops, rest assured — their song “Disgruntled Shooter (In the Nursing Home)” was featured on the “Dr. Demento Show,” and I put their “Fuck You” song on every mixtape I made last year. Digby opens the show, and free bacon will be served between sets. Yes, I said free bacon.