Life on the set of the new NBC comedy Ed can sometimes be as quirky as the show itself. When they're not busy running lines, the stars of the David Letterman-produced series spend their downtime making up songs, bowling and punching each other.

"Everyone on this show is insane," says Jana Marie Hupp, who plays housewife Nancy Burton on Ed, premiering Oct. 8 (8 pm/ET). "We tend to throw each other around a lot. [Josh Randall, who plays Nancy's husband, Mike] is always hitting me. We sock each other. We get in play fights. He throws me up above his head; he picks me up and lifts me around... there's tickling, running around, you know."

In an interview with the TV Guide Channel, Hupp recalls one particularly playful workday that found her horseback riding while co-star Lesley Boone (Molly) played football with the crew. It helps that everything's shot on location in suburban New Jersey, complete with a bowling alley and a fully equipped high school gym. "If they give us any toys, we're like 3-year-olds," says Hupp. "We just go crazy."

And then there's the singing. Julie Bowen, who plays high school teacher Carol Vessey, says the cast likes to perform spontaneous song-and-dance numbers. "We'll make up a song about the lens change ? there's a whole song about 'Nice Tight Lens,'" she says. "There are songs about all the castmembers that make no sense but it keeps the spirits up."

There's an unmistakable bond amongst the Ed troupe, who first got to know each other during the original pilot shoot more than a year ago. "We all live very close to each other and we hang out all the time," says Hupp. "We're lucky there's no big egos. I mean, it's early ? I guess it could happen, but I doubt it strongly."

Not all of their leisure time is spent on the set, however: Boone confesses she sometimes sneaks away for some afternoon shopping. "It's come to the point where literally, I walk out of the set and one of the teamsters will walk up and go, 'So what mall would you like to go to today?'" she says. "I have been to every mall in the New Jersey area because I can't stand just sitting in my trailer