THE TEENAGE ballboy got mugged at midfield. Happened after a Monday Night Football game at the Vet. Six young drunks, reeking of beer, surrounded him, demanding the footballs he was carrying in three bags.

Midnight. Not a cop or a coach or a player or another ballboy around. He tightened his grip. Got punched to his knees. Couldn't fight back because that would have meant losing his grip on the bags.

The kid and his brother Joe had the ballboy job because their father was John Sandusky, the offensive-line coach on an Eagles team that stunk that year. Stank? Whatever. They were putrid.

The Rams clobbered the Eagles 42-3 that night with the fans chanting "Al-po, Al-po" and lugging a huge dog bone around the stands, all because the previous Monday, Tommy Brookshier, then a TV guy, had goaded coach Mike McCormack into saying he had at least two "mutts" on his roster.

The kid remembers turning to his older brother, early in the slaughter, after a pick-six thrown by Mike Boryla and asking, "What do you think this means?" His brother shot back, "It means we're moving."

And after the game, punched to his knees, he remembers peering through the tangle of legs, and seeing the other ballboys, scampering to the rescue. His brother Joe grabs one guy and buckles his knees with a punch to the face that draws blood.

Cops arrive and collar the bad guys. The kids sprint to the Eagles locker room, arriving with a clatter that interrupts McCormack's angry postgame sermon. When he hears what had happened, McCormack turns back to his players and says, "I stand corrected. One member of the team did not turn the goddamn ball over tonight. Well done, Gerry."

That teenage ballboy is an adult now, sports director at WBAL in Baltimore. He has written a powerful book called "Forgotten Sundays," about coming-of-age, about growing up the son of a pro football coach, about lessons learned, about getting sucker punched by life, and getting back up.

It is an inspiring book, a beautiful book, a book for fathers and sons and families of all configurations. His name is Gerry Sandusky. Gerry with a G, but that doesn't stop the taunts and the venom, jerks confusing him with that Jerry Sandusky, the former Penn State coach, the predator jailed now for abusing kids over too many years.

"Hatred," he says now, "is about the hater. It isn't about you."

That is one of the reasons he wrote this poignant memoir, to explain to well-meaning friends why he will not consider changing his name, to explain his stoic stance against the ignorant, to go public with how his family goes forward, heads high.

Nowhere does he quote Shakespeare on "who steals my purse steals trash, but he who filches my good name robs me of that which not enriches him and makes me poor indeed."

"I didn't want to sound highbrow," Sandusky explains. He doesn't sound highbrow, nor does he clutter the book with Xs and Os. He shares the most important thing he learned from his dad, simply told.

"The Colts had lost Super Bowl III to the Jets," Sandusky recalls. "I got into a fight at school afterwards. My father said, 'We have to have a talk.' That meant he would talk and I would listen.

"He said, 'You're gonna meet a lot of jerks along the way. You can't punch 'em all. This storm will pass.' That's a philosophy I draw on to this day."

His brother Joe ["my idol"] dies young. His death shatters the family dynamics, his parents unable to talk their way through the grief. His mother dies.

"I know," he says, "that cancer is physiological. But I believe my mother died of a broken heart."

He does not look back at Philadelphia with anger, even though his dad was fired at the end of three dismal seasons, and he did get mugged at midfield at midnight. Why, you wonder, didn't he just abandon the damn footballs?

"I learned a lot about honesty in Philadelphia," he answers. "My dad had coached in Baltimore, where they won. The Eagles weren't any good and the fans knew it.

"It was a coming-of-age time for me. My first chance to go to training camp, to watch my father coach, doing something he loved with players he loved.

"I was responsible for those footballs. That was my job. I grew up learning that lesson. You did your job. It was win or lose. And I learned what it was like to have true friends. That was my cavalry, coming to my rescue."

He didn't abandon the footballs. He won't change his name. And he has written a terrific book, with lessons for us all.