CHICAGO--Baseball fanatics know only two real ballparks in the major leagues: Boston's Fenway and Chicago's Wrigley Field.

The rest of the Great American Pasttime has moved into kingdoms of billboard-mania, architectural nausea, and modern-day dull. Perhaps the fact that this pair of ballparks also happen to be two of the oldest active structures in the major leagues may have something to do with their special characters. Nonethless, these baseball museums stand far above the rest when it comes to nostalgia and just a good old day at the ballgame.

At Wrigley, nestled into a rejuvenated neighborhood on Chicago's North Side, ivy-covered brick and the absence of lights provide a setting that has been a mainstay of National League competition since the turn of the century.

A billboard across the street, outside the right field fence, challenges the "Cubbies" to "hit one out here," a 600-ft.-plus shot that would tax even the muscle of Chicago strongman Dave "Kong" Kingman.

But the cars, houses and shops that line the streets surrounding Wrigley have proven prime targets for the four-bag shots that regularly pass the low wire fences behind the bleachers. There's no Fenway Green Monster to grab well-tagged liners, and the neighborhood kids make a regular habit of shagging street-bound balls off the bats of major league sluggers: souvenirs that come even without the cost of admission.

Inside Wrigley, though, there is a very distinctive flavor, most of it found among the thin row of bleacher seats that line the left and right field corners. Every ballpark seems to attract its characters in the "cheap seats." Suntan lotion, lots of cold beer and a very vocal commentary on the lighter side of baseball often characterize the bleacher crowd. And the fans at Wrigley are no exception.

In Chicago they've been dubbed the "Bleacher Bums," and they spend the game arguing about location supremacy. The rightfielders yell, "Left Field sucks," and the leftfielder retort with an equally imaginitive barb. And mixed in among the diehard scorekeepers, the beer guzzling fixtures and the cheerleading rowdies, there float the bleacher wisemen--bastions of baseball lore who are no less than bold in making their thoughts well known.

During one game recently, as the second-place Cubs were battling the division-leading Montreal Expos in the last contest of a four game series, one of these bleacher prophets discovered me, taking advantage of a day off and trying to get a tan while the Cubs and the Expos staged their version of Baseball a la Boring.

Montreal had won two of the three games played so far with the Cubs; but ace hurler Rick Reuschel was scheduled to pitch for the Cubs that day, which gave Chicagoans heart. My resident sage, though, had other thoughts.

He was short, squat, and in his sixties, an obvious veteran of baseball history. With blue bermuda shorts and a white T-shirt covering his beer-bloated physique, he looked almost comical. But the man could talk baseball. And talk, and talk, and talk...

"I'll tell you," he said. "I invented this game. They call me Mr. Baseball. You listen to me. I'll tell you right."

The fans around me had turned with a smile, obviously knowing a newcomer was about to get the full treatment from a bleacher sage.

"Let me tell you. This game, I control it," he said. And then, unexpectedly, he shifted gears. "Tell me now, what do you think the odds are?"

"Las Vegas?" I asked, not realizing my faux pas.

"Las Vegas? What's that?" he replied indignantly. "I make the odds. They listen to me. Come on, tell me. The odds. Just a guess. A long shot. Go ahead. Just a guess."