THE CRAZY HORSE has gone upscale? Thankfully, not really. A few changes have been made by management to weed out the rowdies and defuse antagonism in the surrounding Georgetown area, but it's basically the same beer-and-boogie bar that opened its doors on M Street almost 20 years ago. The Crazy Horse still fits one man's definition of a good rock'n'roll club: a place in which most of the patrons have never opened an IRA.

Top-40 clubs have come and gone in Georgetown. In the late '60s, they dotted M Street and Wisconsin Avenue, and bar bands filled the night with one more version of "Proud Mary" and "Knock on Wood." Hordes of college students and high school kids filled such places as the Keg and the French Quarter. Ultimately, however, the clubs dropped from sight, victims of different trends in music and patrons' boredom.

But even with the challenges of disco and punk and new wave and video clubs, there's still a Crazy Horse after all these years, although now it's called J&B's Crazy Horse. Top-40 groups continue to put on the hits of the day, and lines of patrons continue to form sulkily outside on weekend nights.

"The biggest reason is the bands -- the live music," says Stanley Rodzilowski, who has been an assistant manager at the Crazy Horse for almost a year and a half. "You hear the same music on the radio when you go to work and when you come home. People want to hear live music. They don't want to hear any of the 'canned' stuff . . . ."

Rodzilowski says that along M Street, only the nearby Paul Mall also offers live music, and that club attracts more of a suit-and-tie crowd. That's something you haven't seen much of at the Crazy Horse, which for years had the reputation of the bad boy of genteel Georgetown. Hard rock and wet T-shirt nights were among the elements that at times made the Crazy Horse a pretty rowdy spot.

"There's no question about that," Rodzilowski says. "When I came here 16 months ago, it attracted a much rougher crowd. You had a lot of fights, a lot of bums and guys with leather jackets. I remember when I first started here, I'd be working the door and I'd see some young women looking inside, like they'd like to come in. I'd say, 'Why don't you come inside?' And they'd look at me like I was nuts."

He says he and manager Dennis Bonner instituted several changes, including a dress code (no shirts without collars, no flannel shirts), less emphasis on hard rock and more on dance music, and an increase in security. On weekends, the club employs off- duty D.C. cops as security guards, as well as eight beefy, I-mean- business bouncers who make themselves conspicuous.

"I don't know if we had a biker crowd," Rodzilowski said, "but we had some pretty tough people. The age has dropped since, from about 28-29 to about 19 to 25, which is what we wanted." Now, the general look of patrons seems to be a cross between new wave and Prince Georges heavy metal, although he says a better-dressed crowd shows up some weeknights.

There's even an effort at community relations. Rodzilowski says he tries to meet with managers of other establishments on M Street, and lately the club has sponsored benefits for disabled children.

Still, the Crazy Horse's basic mix hasn't changed. It's a long, narrow club with low ceilings, with the bandstand behind the main bar on the left as you go in. Beaten wooden floors and wooden beams give a feeling of homeyness. There are flashing lights, of course, accompanying top-decibel music screaming out of the speaker stacks. A tiny, oppressively hot dance floor is so jammed that the slightest move means bumping into someone else. Under omnipresent Budweiser neon signs, bartenders serve up brews, assembly-line style (Rodzilowski says the club orders more than 300 cases of beer a week from the Budweiser distributor alone). Patrons don't mingle, they jostle. A Saturday night at the Crazy Horse remains the closest thing in this area to putting your head next to the track while a speeding train goes by.

The rush and crush notwithstanding, there's a lot to be said for a place that offers live rock music on a Sunday until 2 a.m. And not a fern in sight, either..

CRAZY HORSE -- 3259 M St. NW. 333-0400. Live bands nightly, $3 cover Friday-Saturday. BEYOND DISCO IN D.C.

Not including such destinations for original pop and big-name acts as the Bayou, the 9:30, Saba, Friendship Station, Kilimanjaro or the Gentry, here are some other clubs in the city offering live pop music:

CLUB SODA -- 3433 Connecticut Avenue NW. Mostly oldies bands on stage Wednesday-Sunday. $4 cover, more for well-known acts. 244-3189.

EARLY LIGHT -- At the Sheraton Washington, 2660 Woodley Road NW. 328- 2000. The Early Light, one of about 89 lounges in the mammoth Sheraton, is the only one with a top-40 band, a polished quartet called Nightlife. Monday through Friday nights. No cover; no cheap drinks.

IBEX MARVIN GAYE ROOM -- 5832 Georgia Ave. NW. 726-1800. Live r&b, rock and soul bands usually Wednesday-Sunday, sometimes Tuesday. This weekend's bill -- the Intruders, and comic Sylvia Traymore, $8 -- is typical at Ibex, which also runs a disco and a jazz lounge on other floors.

PAUL MALL -- 3235 M St. NW. 965-5353. Top-40 bands seven nights a week, $2 cover Friday-Saturday.