At 6:17 tonight, playoff fever officially hit this city.At that minute, Wild Bill Hagy, the Dundalk taxi driver turned Baltimore Oriole cheerleader, stood on a grassy knoll outside Memorial Stadium and opened his mouth.

"OOOOOOOOOOO," he bellowed from behind his bushy red beard.

"00000000000," the gathering crowd responed, and with each letter that ultimately wound up spelling "Orioles," the crescendo grew louder and Wild Bill grew very wild.

Then Wild Bill Hagy turned on his heels and headed for the VIP entrance a few feet away. Children thrust programs at him, asking for his autograph. One fellow offered him a free pair of shoes. "Size 13," Hagy, a 6-foot-3 behemoth, shot back.

When Hagy arrived at the VIP gate, he tried the door and found it locked. He tried two more gates. And found two more locked.

Finally, he presented himself at the press gate, where several friendly ushers recognized him immediately and glad-handed him into the stadium.

Hagy made straight for the dugout for a television spot, and ran into Oriole second base sub Billy Smith en route. "You were there all the way," Smith told Hagy, putting an arm around him and escorting him onto the field.

In a town where blue jeans and T-shirts, polyester and pointy-toed shoes are considered chic, Wild Bill Hagy epitomizes this baseball team of common men. He is one of them, as his friend -- the Spaceman, he calls himself -- pointed out a few minutes later up in Section 34, high in the upper deck where Wild Bill would hold forth tonight.

"Angels," the Spaceman said, refering to the Orioles' opponents tonight. "I don't see no Angels, only millionaries."

Either your're on bus, or you're off the bus, Ken Kesey used to say. Kescy's favorite collor was always orange da-glo. There were 41 da-glo Oriole fans aboard Max Leiderman's No. 1 Baltimore express from Beltway Plaza in Prince George's County to Memorial Stadium.

Max Liederman is a Washington tax accountant who ran Sunday bus trips to Oriole games since April. He grew up one mile from Washington's Griffith Stadium in the days when a kid could get into a ball park for a quarter (he won't reveal his age but he saw Walter Johnson pitch). He believes it is important that Washington youths do not lose touch with major league league baseball. In a summer where all the talk was of bringing the Orioles to Washington, Leiderman brought Washington to the Orioles.

One day last February, maybe March, Liederman was listening to a WRC call-in show. Discussion concerned the possibility of bus service from Washington to the ballpark. Liederman called in.

Now he wears a Baltimore Oriole name tag identifying him as an official team "bus agent". His only pay is his seat and his Oriole cap. "It was the first thing I asked for," Leiderman said. "I said, if I'm going to do any work for the Baltimore Orioles, I've got to have a cap."

His first bus trip on April 8 had seven passengers. During the height of the season, he was running five or six buses. He charges $4 round trip, which is, he says, $4.25 less than Greyhound.

But for the playoff Leiderman has chartered only three buses; for the World Series it may be fewer. Many of his regulars are just regular folk who could not get tickets.

The bus troup was strangely subdued (he allows no drinking). The only noise came from radios turned to Pirates-Reds baseball.

In the front of the bus sat Jerry Mathews, a State Department employe, wearing a White Sox cap. He had a transistor plugged into his ear (you can pretty well tell what time of year it is when grown men walk around with radios dangling from their ears).

Mathews said, "I don't want to tell these people, but actually I'm a California fan; my next post is Tijuana." His last post was Tehran.

Mathews was one of a handful of Americans held hostage in the U.S. embassy during the Iranian revolution. He didn't hear much baseball.

Across the aisle, Dick Cook, who would identify himself only as the singer, was crooning, "Back in the Saddle Again." Was he, too, for the Angels? "Nah," he said "that's where we're going to put Gene Autry (the Angel owner)."

Several rows back was Katherine Martin, a courageous woman wearing a T-shirt that said, "The Orioles, the Right City," with two choices one for Washington and one for Baltimore. Hers was checked "Washington." My husband says I might get mugged tonight," she said.

Katherine Martin and the rest of the passengers agreed that it is the Angels that would be mugged this night. No doubt about it, they said, the O's will win.

Only one voice dissented, Max Leiderman's. "The Senators in five," he said.

Concession stands were everywhere in and around Memorial Stadium, including one operated by the U.S. Postal Service. It offered the best bargain around -- souvenir stamp cancellations on 10-cent postcards.

"Cancellations?" one fan wondered out loud. "You mean people are cancelling their tickets? Maybe I can get a good seat, whaddaya think?" Sorry.

It was easy to get a bad seat. There still were 1,000 obstructed-view seats available two hours before game time and the walk-up business was brisk.

The same could not be said for scalpers' business. One fellow was trying to unload box seats for $20 each and got more catcalls than cash. Finally he gave up and sold them for face value, 90 minutes before the game.

The Memorial Stdium Field, which looked like a pepperoni pizza after the Colts and Bills mauled it in a football game Sunday, was back in respectable shape thanks to two days of manicuring by Pat Santarone, the Birds' green-thumb grounds-keeper.

"Hey, I saw those football guys pouring rubbing alcohol on it." Santarone said. "You ever try to grow grass with rubbing alchol?

But he and his crew had scraped and patted and raked over the bare spots for two days and finally cut out a level, if slightly pock-marked, diamond. One local headline writer said Santarone was the key to the series.

"You're my hero," third baseman Doug DeCines told Santarone. "If it feels like it looks, you're unbelievable."

Santarone is not much of a Colt fan.

"The Colts didn't play here Sunday," he groused. "Buffalo did, but difinitely not the Colts (who are 0-5)."

The best beat in the Baltimore Police Department had to belong to Josiah Massey, one of 60 uniformed cops in the stadium. Officer Massey patrolled the Oriole dugout.

"Just lucky, I guess," Massey said, "although we can't talk to them (the players) and they can't talk to us. Weaver doesn't like it. I think he just wants them to watch the game. So it's not that much. You just sit there."

All three Baltimore newspapers put out special edition Oriole sections today, and one of them contained an advertisement that read:

"Congratulations to Jerold Hoffberger, Hank Eters, Earl Weaver and the Baltimore Orioles and the City of Baltimore on a Great 1979. It has been a tremendous year for the Orioles and the city of Baltimore. Let's do it again next year, together."

The advertisement was signed "Edward Bennett Williams."