In his riveting testimony last week, Lt. Col. Oliver L. North showed a considerable knack for mixing insolence with levity. But he's not the only one. Jokesters all over are diverting their energies to having fun with the Iran-contra hearings, and putting it on the radio.

Setting the pace is the American Comedy Network, a comedy troupe based in Bridgeport, Conn., that has produced a series of commercial spoofs built around North's testimony.

While the music from the Charlie perfume ads plays in the background, a high-energy announcer breaks in with a message for the guy on the spot: "You have to testify before an angry Senate subcommittee and that can really make you sweat," he warns, "so you need the cologne especially formulated to cover that distinctive stench of guilt." Suddenly a singer breaks in with, "You're testifying, but you're caught lying, you're wearing -- Ollie." Of course, this is the "covert cologne" from, who else, "Coverup Cosmetics."

In the obligatory Ronald Reagan spot, a takeoff on a TV commercial for cough medicine, a voice tells listeners, "I'm not a president but I play one in D.C. Hee-hee. And whenever I suffer from political headaches or, ah, ah, memory congestion, I get fast, fast relief with 'Poindexter's Formula 44.' " To the background sound of liquid being poured into a spoon, "Reagan" continues: "Just three quick hits of this, hmmmm, soothes my conscience. And, helps me sleep. All night. All day. All year. Zzzzzzzzz. I didn't know nothing. Oliver North ... he ... did ... it ... all."

Then there's "The All New Washington, D.C., Senate Subcommittee Production of 'Oliver,' " a musical satire that bears a remarkable resemblance to the radio advertisement used several years ago to promote the Broadway play. That's because, according to ACN spokesman Stephen Ban, the five-member troupe hired unemployed Broadway actors and singers to produce the spot. "In this 'Oliver,' Fagan's boys are now Reagan's boys. Picking America's pocket and stealing your heart," the announcer says. Listeners are advised to "catch his unbelievable song and dance. Take the kids. Take the Fifth. Now and forever at the Watergate Theater."

The joke service, geared to radio stations' morning shows, is sold to only one station per market for an annual fee of $13,500. The ACN service was recently dropped by local WRQX-FM (107.3), but it is heard on WIYY-FM (97.9) in Baltimore.

Others have gotten into the groove, too. Take Sean and Eva Trachtman. The Burke couple, who bill themselves as The Fifth Amendment, have released their own version of Chuck Berry's "Johnny B. Goode," dubbed "Ollie Be Good." One verse tells the story this way: The old man came to Ollie, said we need a scheme

One night he came to Ollie when he had a dream

We'll send the Ayatollah missiles and a cake

Collecting all the money for the contras' sake

We funnel all the money through a Swiss account

And no one gives a damn if it don't balance out.

Go! Go! Go, Ollie, go!

Go! Go! Go, Ollie go!

Go! Go! Go, Ollie go!

Ollie be good! The song debuted on WCXR-FM (105.9) and is now being heard also on WWDC-FM (101.1).

Richard Siegel of Greenbelt penned his own words to the Grateful Dead's "Friend of the Devil" called "Friend of the Ayatollah," which has gotten airplay on WHFS-FM (99.1), WPFW-FM (89.3), DC-101 and Baltimore's WIYY.

Other local radio stations have also taken advantage of the interest in the hearings. WAVA-FM (105.1) is offering listeners "Ollie Kits" that include a $10 traveler's check, a $3 gift certificate to Parklane Hosiery, a coupon for an "Ollie Burger" at a local burger joint, a security system (actually, just a padlock and key set) and a manual shredder (scissors, of course).

At Manassas' WMJR-FM (107.7), listeners who call in "at the sound of the shredder" get a "Virginia is for shredders" T-shirt. Why? "Because Fawn Hall is from Annandale and Ollie is from Great Falls," brags Operations Director Mark Lapidus.

That station will hold a "Shred-Off" on Thursday. The winner gets a complete home security system.