The party began at Georgia and U streets.

Jimmy (Bo) Horne came on loud out of a hand-held radio inviting everybody to - "Get up, let's dance, let's do it some more, get outa your seat, get out on the floor." - and Stanley Owens was dancing in his seat, first tapping his foot and then tapping the girl by the window to ask her if she rides this bus, the Navy Yard bus, everyday.

In the back of the bus, it's a party.

"Twenty years ago you couldn't get nobody to ride in the back of the bus," Troy Green said while riding the L-2 bus to Chevy Chase. "Now they don't want to sit nowhere else."

Those who don't want to sit back there sit up front - as far away from the rear as they can get. Bus drivers complain that they can't control what goes on back there. But to those who prefer the rear, it is the place to sit for rolling around the city in air conditioned comfort, talking to women, meeting men, leaning out the windows and seeing what's happening, getting high on "smoke," and making the bus ride a real "trip."

"It's like a club," said Richard Johnson, who picked up the D.C. General bus at 18th Street and Columbia Road N.W. "You get on with a couple of your friends, so most likely you're going to be having fun and maybe somebody's got something left over from school or whatever so you just go ahead and fire it up. And if somebody's got music, then that's on, too."

The club is mostly young and black and it includes the people out in the street as well as the people in the back of the bus.

When the bus - any bust - snorts up to a bus stop to pick up passengers, part of the waiting crowd lines up at the front door to pay their fares while another group gathers outside the bus' rear windows.

"Got any tarnsfers?" the people in the street shout up to those in the back of the bus. "Got any transfers anybody?" and somebody in the back will give the rider sitting in the back corner seat a transfer so he can hand it out the window. Then, before the bus can pull away, another rider bounds on board, waves the transfer at the bus driver and joins the back of the bus for free.

Even better, the back of the bus crowd will tell you, is what happens sometimes when the bus pulls up to a school or crowded bus stop. Someone holds the doors open, letting everyone on free, and the bus driver never says a word or tells anyone to get off. Everyone sits in the back and enjoys a free ride courtesy of the back of the bus.

"All these people getting on, getting high, what can they say, anyhow?" asked Teena McMillian, a regular rider on the Congress Heights bus. "What should they say, anyway? The people back here aren't hurting anybody and it would just hold up the people in the front of the bus for the bus driver to be back here arguing."

In the back of the bus, as the city whizzes by on all sides, there is talk about whatever comes up, flirtations that end up with the exchange of phone numbers, a friendly passing of the beer can in the brown bag in the street corner tradition and the intimate sharing of a marijuana cigarette by strangers.

"I just like to sit back there and listen to people arguing," McMillian said. "And if they say anything about clothes or shoes, if they say Saks, she said, looking at her friend Joy Shorter, "I know you'll be in there screaming something."

"The back of the bus is where everything happens," Shorter said. "You can hear about whatever's happening in town. You can be way up in Northwest and hear about what happened last night in Southeast. It's like that. And if someone starts saying something about clothes or shoes, I'm going to try and set them straight because I know about clothes and shoes, and if I'm excited, you know, you got to speak up, maybe scream. That's what she (McMillian) is talking about."

McMillian and Shorter said they never really gave anyone their real phone numbers after they meet them in the back of the bus. "They'll sit down next to you and ask you some sort of thing," McMillian said, "and then they want your number. I just give them any old number. You might not see them again for a couple of months. The faces on the bus change everyday."

On the Benning Heights bus, Eugene Webster, who was wearing large blue and white plastic eyeglass frames without the lenses, got a girl's phone number after talking to her and sharing with her Fritos, Twinkies, an orange soda and, finally, his Kool cigarettes.

"Hey, I don't get no phony numbers," he said. "I don't know about you, but these girls are out here, you know. You just got to treat them right."

Later Webster added, "I meet them (women) everywhere but . . . you can meet lots of them on the bus. Like if they're in the back, it's easy to get to talking to them. Everybody else is talking about something, so right there you got a way to start something . . ."

During the morning and early afternoon, several of the persons in the back of the bus are unemployed workers who prefer riding the bus to sitting at home.

Calvin Josnson, an unemployed painter who was on the 14th and Decatur Streets bus one morning recently, called the bus his "limo" (limousine).

"It's air conditioned like a movie (theater) but it's cheaper," he said, laughing. "I get to see all of my friends around town, see what's happening and it doesn't cost a dime. It keeps you alive, you know, keeps you in touch with people . . . It's my limo."

As the bus traveled up 14th Street, Johnson, who lives in Southeast, slid the last window on his side of the bus-forward and waved to friend after friend as the bus roared on.

At 14th and R streets he pushed the back door open and stood talking to a friend. The bus driver waited a moment then shouted to Johnson to close the door. Johnson kept talking but retreated one step back into the bus.

"Jump on, man, let's ride," he said to his friend, who said he couldn't, explaining he had something to do.

"I just learned to ride the bus," Johnson said when he got back in his seat."I used to pay everytime and sit up front alone. That's for loners. That ain't what riding this bus is about."