In the middle of tonight's Steve Martin special on NBC, an announcer says, "we'll return with 'All Commercials' after these messages." Oh, the bittersweet irony! Martin opens "All Commercials," at 10 on Channel 4, by asking, "How often have you had to sit through those boring entertainment shows just to get to those great commercials?"

This is after a dance number featuring Mr. Peanut, Mr. Clean and a woman with a toilet paper hat. Martin comes out as a ketchup bottle and whoa boy, there's some fun for one and all. The commercial spoofs range from a musical on behalf of Truman Capote jeans to a discreet spiel for "You Know," a feminine product whose precise function must be couched in delicate euphemism.

Some sketches work, some implode, but the level of writing is pretty high and the hour occasionally riotous. Indispensable among the cast are Anne Lockhart, a surprisingly fresh comedienne, and Louis Nye, who is, not surprisingly at all, hilarious -- just the sight of him is a tonic.

In a sketch about a desperate ad agency searching for a client, Nye waltzes in as the president of Okra Cola, a foul concoction that leaves the Okra Generation with green mustaches and impaired faculties. "I wouldn't feed this stuff to my own kids," says Nye, "but I expect to shove it down the throats of America." The agency obliges with a hlarious dipso-Pepso ad.

Three real commercials, from abroad, are shown, including John ("Monty Python") Cleese terrorizing passersby for a watch company, and the Japanese soap ad featuring naked tots and a sure-fire kicker first shown on "The Tonight Show" several years ago. Comic Robert Klein does a too-brief monologue on commercials after Martin's introduction, "One of the great things about being a Hollywood phony is that you get to introduce everyone as your closest friend."

Some opportunities -- including Martin in a merry prop Morris-the-Cat suit -- are muffed, but many more succeed. This steve Martin special is stronger than dirt, twice as fast as aspirin, and contains more of the pain reliever doctors recommend most.