According to Dave, the matinees were the same in Philly as in Annapolis. Kids, mostly boys, began gathering outside the theater doors a half hour before the one o’clock show. Nine, ten, eleven years old, they chased around, punched arms, flicked ears _ in general, worked themselves up for mayhem.

By ten before one, they were piled against the glass doors, strata of grinning faces, almost halfway up. From inside, they looked like a pirhana school.

When the doors were unlocked, some just fell onto the lobby floor, while the rest spilled over them.

The mob streamed through the lobby and quickly filled the house from front to back. Until the lights went down, the kids bounced around in the seats, made vulgar honks with their candy boxes, threw jujubes at one another. But the movie’s opening always got them still. They leaned forward, eyes riveted to the screen.

Those old oaters generally opened with villains blowing up a mine; or a bar fight, broken furniture, and somebody flung through the front window; or with a runaway stagecoach, driver shot and fallen from the box, wild-eyed horses dragging the whole rig straight for a cliff. When the hero showed up, the mass of kids cheered as if they’d formed a single organism _ which, come to think of it, is what defines a mob.

Action, lots of it, held the kids in check. What the Philly ushers dreaded, said Dave, was the first romantic scene. And such a scene made the basis for his story.

It was in a Roy Rogers western, and Roy had already punched out the bad guys in the bar. (Roy never shot people, though sometimes he shot guns out of their hands and left them wincing.) But now the scene had shifted to a ranch house porch.

It was evening; Roy and Dale Evans were side by side on a porch swing as he serenaded her. Just off to the side, chaperoning, I guess, were Roy’s backup singers, the Sons of the Pioneers.

They were in fringed shirts and neckerchiefs, and they looked, as always, solemn and a little pained. The Sons strummed their guitars and filled in behind Roy’s voice with humming and melodic woo-ah-woo’s.

Out front, the kids made their own sounds _ groans, catcalls, loud gagging. Meanwhile, Roy’s singing face often filled the whole screen, all earnest and tender. It alternated with reaction shots of dewy-eyed Dale. The singing, the woo-wooing, the lovelorn looks dragged on and on. And finally they became too much for some anonymous kid, out there in the dark.

That Philly theater should never have sold frozen stuff at the candy counter. But it did _ congealed sugar water in varied chemical shades and, top of the line, chocobars: pretend vanilla ice cream coated with waxy brown chocolate. (You held the chocobar by its stick, tried to finish before dribbles ran up to your elbow.)

In the middle of Roy’s love song, said Dave, a chocobar came spinning out of the darkness. In a high trajectory, it flashed briefly through the shaft of light from the projector. Then it struck old Roy right on his high, virtuous forehead, just below the hairline.

Roy’s face was full-screen just then, his slightly squinty eyes damp and soulful. When the chocobar hit him, he didn’t even flinch, kept right on singing, even as the melting bar slid across his right eyeball and started down his cheek.

The delighted kids roared, whooped, whistled. This was just too good!

Then came a wide shot _ Dale facing Roy, eyes locked, both exuding warmth. But now the bar described a chocolate smear between the sweethearts.

They ignored it, as did the Sons of the Pioneers, who kept humming and woo-wooing. The kids, of course, were screaming, cackling, out of control.

Now Dale’s face filled the screen, tears welling in her eyes. And no wonder. The chocolate smear split her visage, top to bottom, and started down the front of her buttonedûup blouse.

The kids were standing on the seats now, roaring, gasping, choking with laughter. If there weren’t a lot of wet pants out there, I’d be surprised.

But then it all ended. Abruptly the screen went dark. House lights snapped on at full power.

Kids first shielded their eyes, then looked toward the stage. On it, standing at the foot of the besmirched screen, was the manager. And at the head of each aisle stood a burly Philly cop, scowling at them. The kids went quiet.

"Show’s over," barked the manager. "Leave. Now."

And those hundreds of kids did, meekly peeling out of the rows, front to back, as if this were church, not a theater, and those burly cops were iron-faced nuns. Some kids, trapped by habit, even genuflected as they left the rows.

On the sidewalk, of course, the riot began again. Laughing kids leaned against walls, parked cars, one another. Kids fell down, rolling on the pavement. If the laughter waned, some kid would gasp, "Woo-ah-woo!" and it would start all over.

I’ll bet to this day in West Philly bars, if someone brings up Roy and the chocobar, gray-haired, paunchy men will get to laughing, and laugh till they cry.

Dave said, by the way, that by the next Saturday, the cooler was gone from the lobby. No more chocobars.

Jim Atwell lives in and views life from Fly Creek. Learn about his book at JimAtwell.com.