Underground Theatre Conspiracy, at Sheffield’s.

Just being a mostly black comedy troupe allows you to do jokes other companies can’t–like the crime quiz show where the prime suspect is always the black guy with the stocking over his head or a running gag about dances black people must never do in public (the bunny hop, slam dancing, and the Russian tea dance).

But these five merry yuksters, backed up by Raenon Teller on a fluid synthesizer, don’t just skewer racial stereotypes. In improvised and written sketches they target frustrated Method directors who terrorize kiddie pageants, the GOP’s contract on America, Amish comedians, gun-worshiping rap musicians, and even, in the most tasteless bit, the lazy art of mime for the blind.

Though most are easily familiar, at least one of their improv bits offers a clever innovation: in “Diminishing Returns” the audience suggests ideas for increasingly shorter skits of 60, 40, 20, 10, 5, and finally 1 second. In another an audience member supplies clues about his life, on the basis of which the two women in the troupe compose a love ballad. In a third winner, Crystal Marie Smith is deftly phony as a cerebral WTTW interviewer. Of course not everything clicks. A sketch about a coin-operated confessional gets old quickly, and one about a former gay bar haunted by its old patrons never improves on its stretched premise.

But the confident and individually adept troupe deliver laughs–especially Shaun Landry, whose feminist poet rages magnificently over a toilet seat left up, and Hans Summers, whose twerpy tot proves instantly endearing.