he old gym at Fort Myer wasn’t much to look at. Even after you were in your seat, you wondered if college teams played there. Those that did, such as American University and George Washington, were sometimes good, never great. But it was the place where plenty of people got their break in the shallow end of the big time, such as Gary Williams.

As soon as you first saw Williams, coaching AU from 1978 to 1982, you knew he was destined for great things. Or else, for a padded room. He was crazy. Good crazy.

You would grab him for a quote as he strutted off the court, but your hand would slip because everything he wore was sopping wet. In 33 years, he has barely changed except somebody pruned his face and slipped a gray wig on him. The body’s rail lean; he’s still coaching on his haunches. Or he did until he hung up his straitjacket for good this week.

“AU was playing Georgetown at Fort Myer — one of those great games,” he said Friday at the zillion-dollar Comcast Center that everyone calls The House That Gary Built. “Back then, we got $3 in meal money for every player, all in $1 bills. You hoped a team manager wouldn’t show up, so you could keep an extra $3 for yourself.”

Gary had those dozens of $1 bills rolled up tight in a rubber band in his coat. Then something snapped. Something always snaps with Gary. That’s what’s best about him. But this time, in manic mid-pirouette, it was the rubber band that snapped as Williams twirled.

“All the dollar bills flew all over the place,” Williams remembered Friday. “Joe Forte was the referee. I thought for sure he’d give me a technical.”

But the whistle didn’t blow. Around Washington, everybody in basketball has always cut Gary a little extra slack. They like him and his mordant humor. And he’s obviously the hoop life force incarnate. Also, he gets that slack, that good-crazy extra rope, because at some level, he needs it to function. Rein him, you choke him. For 15 years, Debbie Yow never got that. She liked the results but wanted to change the man.

So Forte let Williams bend over and pick up every bill on the court, one by one, during a free throw. “Then he teed me up five minutes later,” Williams said.

In his world, Gary Williams knew how every single thing should work, how to run the passing game, how to spot a Juan Dixon that nobody else would recruit or how long a ref would wait before he called that make-up technical foul for the cloud of dollar bills.

Now, Williams is leaving the tiny-yet-enormous cocoon called basketball that has enveloped him since “I was 5 years old,” he said, crying a little. Everybody worries about him, just a little, because he isn’t joking when he says, “I’m kind of ‘out there’ now. It really feels different. Besides the coaching thing, I’m basically unskilled.

“We’ll see what’s next. I feel relatively healthy, got a new wife. We’ll see what happens. Not about the wife. Hey, that didn’t come out right,” he said, getting a smile from Dana and a guaranteed laugh line from a couple of thousand people who had come to Comcast Center just to chant “Gary, Gary, Gary,” and “Thank you, Thank you.”

Maryland President Wallace Loh drained a trey when he said, “The front porch of a house is the most visible part of the house. Intercollegiate athletics is the front porch of this university — the most visible part. We have risen dramatically in the last 20 years into a great research university. A key factor in the rise of Maryland is Gary.”

Then he mentioned that $800 million fund raising drive and how Williams was “instrumental in raising $240 million in aid for our university students.”

Guess that shows how far you can come from a pocket full of $1 bills in a rubber band — that is if you wake up every day and work like, well, crazy.

Sitting in a catbird seat of a job at Ohio State, Williams came back to his alma mater 22 years ago to save the program — built into a power by Lefty Driesell, then demolished into NCAA probation by scandal. The smart money said it was a dumb call, but Gary did it for love. He has flaws and knows it, but his core emotion always carries the day for him. The heart on his sleeve isn’t rented; it’s real. And the tears the night he cut down the net after the Terps’ national title in ’02 weren’t for the cameras. Walking in a tunnel that night, I wanted to say, “Stop crying. Just answer the questions.”

And, yes, he does play by the rules, too. Part of that is ethics. But part, I think, is because he’s the best game coach and upset-motivator I’ve ever seen, including Bobby Knight and that coach who goes by one initial at Duke. And Gary loves the Robert E. Lee role, playing that outmanned genius general. He’ll retire tied for the career record by beating seven No. 1-ranked teams. Gary, log firmly on shoulder, loves to beat you with less, then bask in the obvious.

Maryland students loved Gary because he fit them. If he spun in the air pumping his fist and his shirttail came out, all the better. Who says we can’t beat those stuck-up Dukies if we try hard enough? My son, a recent Maryland grad, phoned me from Comcast Center during the 2009-10 season, when Gary and Maryland were on the way to being ACC regular season co-champs.

“Are you watching on TV?” my son screamed over the crowd. “We’re getting ready to storm the court. Gary is going to beat North Carolina!”

For 22 years, but no more, they were indissoluble and indefatigable: Garyland, our Garyland.