On Friday nights at midnight and Saturdays at 11 p.m., the USA Network’s USA: Up All Night show hauls out a triple feature of junky exploitation films like Satan’s Cheerleaders, Hot Summer in Barefoot County, and A Nymphoid Barbarian in Dinosaur Hell. Most of these movies aren’t worth more than a glance and a snicker, but USA has found a way to keep at least some of us hooked by having this ongoing schlock film festival overseen by two amusing comedians. On Fridays, there’s Rhonda Shear, a stand-up comic who combines a sharp mind with a sex-bomb exterior to create shrewd, lewd humor. On Saturdays, Gilbert Gottfried presides. As he does on talk shows and in movies like Beverly Hills Cop 2 and The Adventures of Ford Fairlane, Gottfried YELLS EVERYTHING HE SAYS, LIKE THIS! Scrunching up his eyes and bellowing a mile a minute, Gottfried is a bit more surreal than Shear (he once did an entire show as a disembodied head nestled in the garbage of a New York City trash can). Gottfried and Shear are seen during the show’s bumpers — TV talk for the brief moments before and after the commercials. The hosts’ ostensible function is to set up the movie’s next scene (Gottfried: ”Now, back to the movie that proves there are worse actors around than McLean Stevenson ”), but what they’re really doing is providing more entertainment than the movies themselves.