”We have the feeling that we’re dorkier than anyone we could make fun of,” says Joey Garfield, one of the seven Wisconsinites in New York collectively called the Bert Fershners. Maybe that’s why they don’t mock or tease others. They’ll be poking fun at themselves much more: On Aug. 13, they start a run of Tuesday-night sketch-comedy shows at Manhattan’s Kraine Theater, and Comedy Central has just appointed them in-house jesters, essentially making them the cable network’s Monty Python; their short films are now airing, and they’re taping a fall series pilot. The Fershners — politely goofy men in their late 20s and early 30s — favor offbeat situations that ”aren’t gender-specific,” jokes Chris Tallman. Says Dan Fleming, ”We’re very serious about silly things.” One number, ”Left Foot,” turns names of body parts into a catchy chant. Like the group, it’s not angry or edgy — just very silly and very funny.