Observational humor had been George Carlin's specialty for over 20 years when "Playing with Your Head"--the comedian's fifth special for HBO--was recorded in 1986. Carlin's not resting on his laurels here, presenting an abundance of new, politically incorrect material while expanding a few older routines. In "Sports" he applies hilarious criteria to what does or doesn't qualify (hockey doesn't count; lacrosse is a "faggot college activity"), and "A Moment of Silence" pays mock-mournful tribute to an ill-fated (and presumably fictional) group of "43 elderly, mentally retarded Bolivian senior citizen volleyball fans." If that kind of irreverence puts you off (and if so, why are you reading this?), you'll fare better with the universal humor of "Losing Things" (we all do it, right?), and a characteristic survey of language in "Hello and Goodbye." In any case, Carlin's best enjoyed when seen "and" heard, and the film noir spoof "The Envelope" provides a clever introduction to the funnyman's entrance onstage. "--Jeff Shannon"