It's 7:45 on your typical WKYS morning--this one happened to be last week--and drive-time hosts Russ Parr and Olivia Fox are in the middle of one of their regular comedy-bits-with-a-message. This routine has to do with a survey Fox found showing that blacks go to the dentist about half as often as whites.

At their studio in Lanham, they take what sounds like a call from a listener complaining--through what sounds like a mouthful of cotton--that the study is "racist." But under humorous questioning by Parr and Fox, it turns out that the caller gets to the dentist only "every couple years or so" and, in fact, is even missing a few teeth.

"You sound like it," Fox says. "How many teeth are you missing?"

"Fee or foe," he says.

"Three or four?" Fox translates.

"And what is the advantage of going through life like this?" Parr asks, setting up the punch line.

The caller doesn't miss a beat: "I don't have to floss."

Parr and Fox, on black-hits WKYS (93.9), recently were named Washington's best morning-show personalities by the March of Dimes, which gives the annual Achievement in Radio Awards, and by Airplay Monitor, a Billboard publication.

In the most recent Arbitron report, released last month, Parr and Fox dominated the ratings in their target market, listeners 18 to 34, beating out Howard Stern (WJFK). Moreover, in January they were syndicated to their first out-of-town markets--Philadelphia and Detroit--and have since added seven more.

For three years, the widely syndicated, laugh-it-up "Tom Joyner Morning Show" (heard locally on WHUR) and the smooth and decorous "Donnie Simpson Show" (WPGC) have ruled area ratings among morning shows on black stations. But right now, it's the ascendant Parr and Fox who seem to be on a roll.

They mix comedy and real and fake callers with black hits, and even toss in surprise songs such as an occasional Rolling Stones tune on "Wrong Song" days. They've been doing the show together since 1996.

"I knew after talking to Olivia once or twice that she was the one," Parr said in an interview last week. "She found me funny, and not very many people do." Parr is married, has four children, is "in my early forties" and wears a hair weave.

He runs his own sound board to ensure split-second timing; "two-tenths of a second [of dead air]," he said, "can kill a joke."

Said Fox, who is 34, single and "looking": "Next to my father, [Parr] is one of the funniest people I know. He makes me laugh to the point of crying once or twice a morning."

Parr had been a deejay in Los Angeles (where he was a "terrible" stand-up comedian, he says) and in Dallas before taking over the WKYS morning show. Fox, who had worked part time off-air at Washington's WHUR and as a deejay in Philadelphia, came on board about six months after Parr.

"When I met Olivia, I told her, 'I'm looking for someone who can stand up for women,' and boy, she went off," Parr said. "And I didn't want someone just coming off like an angry black woman."

"What is lacking in radio is women having a voice on the air outside of just being dumb or being the butt of jokes," Fox added. "I've never been that type of jock."

Once their four-hour daily shift ends at 10 a.m., Parr and Fox stay in touch via cell phone. "I may call Russ 10 times a day, saying stuff like, 'Turn on Oprah,' " Fox said. "It's how we get ideas for the show."

The show's move into syndication hasn't hurt the content; each city drops in its own traffic and weather during breaks. Fox said, "The people in Cleveland think we're there," and the same is true in the show's other cities.

The morning crew is rounded out by executive producer Ted Carter, who frequently appears on-air (he voiced the toothless caller); assistant producer Brian Brown, who goes by "B Plus" on the air; and other regulars who like to remain known only by nicknames: sports reporter "Supa Ken" and "Lazy Lamont," a station engineer who parodies rappers.

Morning shows are at their best when they connect with listeners, and Parr and Fox go to great lengths to do so. They mirror listeners' foibles through gentle parody (such as the no-account, toothless caller) and recognizable characters such as Danielle, the Cell Phone Sister. Danielle, a mythical regular, pretends to phone in from traffic and, in the middle of happy banter, explodes into hilarious, bleeped-out profanity at her fellow drivers.

"Stop looking at me and cross the damn street!" Danielle shouted at a pedestrian one day last week.

Parr came up with the character, voiced by WKYS employee Shalita Washington, after a real-life call one day from Fox, from her car. During an otherwise mild conversation, Fox let out an epithet stream at another driver.

"I said, 'Did Olivia just call me [an expletive]?' " Parr said. "I realized all of us get like that when we drive." He and Fox created Danielle as a way for their frustrated morning-commute listeners to vent vicariously.

A more direct listener lure is the weekly "Hook 'Em Up Wednesday," in which the show turns into a dating service. The lovelorn phone in a brief personal ad, and Parr and Fox seek a match. Occasionally the show takes on a theme, such as "Over 300" day, in which only callers who weigh more than 300 pounds are allowed to participate. Naturally, hilarity ensues.

But what makes Parr and Fox a cut above your average morning zoo show is that they sometimes deal with issues that get under listeners' skin.

They started "Gay Hook 'Em Up Wednesdays." "A lot of gay black people are single, and we thought it made no difference what their sexual orientation was," Parr said.

Added Fox: "A lot of people in the black community pretend homosexuality doesn't exist."

As expected, these shows unleash a flurry of calls: from grateful gay listeners, from older Christian ladies preaching fire and brimstone and from black men spouting homophobia, Parr and Fox said.

"We weren't doing it to shock people; we did it because it's what we believe in," Parr said. Not to mention that "a lot of gay black folks have [Arbitron ratings] diaries."

Working in favor of Parr and Fox's rapid-fire comic improvisation, they say, is the sophistication of the Washington audience.

"In other markets, a lot of my humor goes way over their heads. You have to spell it out," Parr said. And, he says, the District's audience is opinionated and expressive. "I'll go out to Republic Gardens, and folks will argue with me over something that was on the show. I like being in a town where there's a healthy debate."

Wagner Leaves WTOP

Veteran crime reporter Paul Wagner is leaving all-news WTOP (1500 AM) for Fox TV-Channel 5, where he will report on crime and other news starting Nov. 29.

In his 11 years at WTOP, Wagner developed a reputation as a terrific street reporter, breaking crime stories frequently followed by local TV and newspapers. Now he heeds the siren call of TV.

"I'll miss the immediacy of getting stories on the air as soon as I confirm them, and I'll miss going to work in bluejeans," says Wagner, 43. "But it's something I've been watching from a distance for quite a while, and I'm anxious to try it."

Channel 5 and WJLA-Channel 7 had each approached Wagner; the Fox station offered a contract, while WJLA wanted to hire him as a freelancer while he stayed at WTOP, he said. WTOP matched the Channel 5 offer in an effort to keep him.

In radio, Wagner said, he got 30 seconds to tell his stories. On TV, he anticipates having 90 seconds. While at WTOP, Wagner broke the story of the alleged confession in the Starbucks slaying case and, in 1991, he won the Edward R. Murrow national award for spot news for his reporting on the Mount Pleasant riots.

Chat live with The Listener today at 1 p.m. at www.washingtonpost.com/liveonline/. You'll be glad you did.

CAPTION: Olivia Fox and Russ Parr say Washington's sophisticated listeners are the ideal audience for their rapid-fire comic improvisation.