Jim Schramm and his boomerang buddies know many people see their sport as odd.
That's one of the reasons they like it.
"There aren't that many of us out there," said Jim, 47, a systems engineer from Ferguson, Mo. "And one way or another, we all know each other. There's like 2 degrees of separation.
"Especially with social media, you get friend requests from Germany, New Zealand, Japan, all over the place."
About 20 throwers will gather May 25 at Konarcik Park in Waterloo for the 27th annual Gateway Classic Boomerang Tournament.
The public is invited to watch at no charge and, if desired, bring a picnic.
The tournament attracts only a handful of spectators, not enough for a concession stand, but it's the largest in the country for number of competitors.
"We get more than the national championship," said organizer Bob Leifeld, 46, of Waterloo, a Boeing programmer analyst who once made and sold boomerangs for a living.
Throwers will include Jacques Sabrie, 47, of Waterloo, a computer engineer at Scott Air Force Base. He got Bob and Jim into the sport, after the three attended St. Henry's Preparatory Seminary in Belleville.
In 1987, Jacques competed for the United States at the World Boomerang Team Cup.
"I like things that fly," he said. "And it was just different. It wasn't something everybody else was doing. I started making my own boomerangs, and I enjoyed the craftsmanship."
Bob and Jim also have entered tournaments around the country.
The sport's main goal is to throw a boomerang so that it returns close enough to catch.
Competitions add to the challenge with events such as trick catch, fast catch, accuracy and endurance.
"With maximum time aloft, you're trying to keep it in the air as long as possible," Bob said.
"You use a specially made boomerang. It's like a maple leaf. It will keep spinning and spinning and spinning. It will go really high and then it will just hover down slowly."
Boomerangs can be made of thin aircraft plywood, polypropylene and other plastics, aluminum, even nylon. They come in all shapes and sizes for different events and weather conditions.
Some are striped, polka-dotted or made to look like characters such as Batman or Gumbie.
"I have 50 in my competition bag, and then I probably have another 100 at home," Bob said.
"Some are just for fun. Some have been retired because the technology is obsolete. Some of them I've made, and they just didn't pass muster."
On a recent weeknight, Bob, Jim and Jacques met up with fellow boomerang enthusiasts Tom Fitzgerald and Isaac Syler for practice at Konarcik Park.
They had their work cut out for them. Bob used a hand-held gauge to clock winds up to 18 mph.
"It's more like a kite day than a boomerang day," Jim said.
Bob failed to catch his first three throws but succeeded on his next three, then kept going with mixed results.
He mostly ignored the jokes and snide comments from his friends, who were huddled around gym bags and cases full of boomerangs.
Socializing and camaraderie are a big part of the sport's appeal.
"Unlike Frisbee, where you're far away from each other and you've got to yell to talk, with boomerang throwing, you're all standing together," Tom said. "You can laugh and have fun."
Tom, 60, of Hazelwood, Missouri, founded the St. Louis Boomerang Club in the mid-1980s and co-organized the first Gateway Classic.
He bought his first boomerang on a whim and took it to a picnic but couldn't get it to return.
"It was embarrassing," said Tom, a baker with St. Louis Bread Co. "A grown man throwing a stick around.
"So I put it in a drawer, and I left it in there for years. Then I got it back out again for some reason, and I threw it, and it came back, and I was hooked from then on."
Isaac's involvement increased more gradually. He started throwing boomerangs in 1985, learned to catch in 1995 and discovered tournaments in 2005.
The 33-year-old Java web developer from Shiloh proudly lifts his bangs to reveal a small battle scar on his forehead.
"What do you expect?" he said. "You are throwing things at yourself."
The Gateway Classic started at Forest Park and stayed in St. Louis for more than 10 years. It eventually made its way to Waterloo in 2006.
The tournament is sanctioned by the U.S. Boomerang Association.
The sport's popularity has dropped in recent years, judging by association membership and number of tournaments. But that doesn't discourage Bob.
"In the beginning I just loved boomerangs," he said. "You'd throw them, and they'd come back to you.
"But now that I'm older and less competitive, it's mostly the people (that keep me going). It's a great group of people."
At a glance
What: 27th annual Gateway Classic Boomerang Tournament
Where: Konarcik Park, west of Waterloo on Konarcik Road (Fourth Street)
When: 9 a.m. to 6 p.m. May 25
Information: 618-939-9023 or firstname.lastname@example.org