The secret to Coed Prison Sluts, which most of its many imitators miss, is that it's a carefully constructed satire masquerading as an artless mess. Faith Soloway's hilarious, well-written songs artfully mate sweet, sappy, very pop tunes (reminiscent of the mindlessly happy songs people sing in children's television) with taboo-breaking lyrics ("Shit! Motherfucker! Hey! You cunt!" Or "You prick! Blowjob! Suck my dick!"). Likewise, the screwy plot, developed through improvisation under Mick Napier's watchful eye, wittily marries the cliches of prison movies--the deadening daily routine, the underground prison economy, the climactic showdown between the good prisoner and his archenemy--and those of old-fashioned musical comedies: the cute meet, the relationship-threatening conflict, even the traditional pair of couples, the leads meant for romance and the others for comic relief. This show is so well made that five-plus years after its opening it remains as funny as ever. In fact it's funnier. The performers, many of whom originated the roles, have become seasoned and self-assured comic actors, and keyboardist Lisa Yeargan brings out the subtleties in Soloway's tunes much better than Soloway ever did. Annoyance Theatre, 3747 N. Clark, 929-6200. Open run: Fridays-Saturdays, 10:31 PM. $10.