"They moved away or they moved on, or they got successful in their careers and they didn't have time to do ComedySportz anymore. People like [1812 Productions co-founder and First Lady of Philly comedy] Jen Childs and Scott Greer. They are two local names who did ComedySportz for years when they first started out in Philadelphia."
Another returning alum is Tom Fowler, who, since leaving for Los Angeles a couple of years ago, has appeared in TV commercials and in several skits on "Jimmy Kimmel Live."
The anniversary presentation will look familiar to those familiar with the ComedySportz format. Two teams - dubbed, as always, the Philadelphia Fighting Amish and the New Jersey Turnpikes - will face-off in a series of "games," among them "Story" and "Forward/Reverse."
In the former, Motrey explained, "The entire team lines up on stage and the ref conducts a story. The players have to make it up as they go along, and they have to be able to cut off their words if the ref points to someone else. The person he points to has to come in in the middle of that word and continue the story."
"'Forward/Reverse,' " he continued, is a 'scene game.' At any point, the ref will blow the whistle and say, 'Reverse,' and the scene has to move totally backwards until the ref says, 'Forward.' "
For sheer silliness, nothing likely beats "Oxygen Deprivation," a competition that involves contestants dunking their heads in a bucket of water, then having to make up a story as to why they are wet.
There are few things more subjective than humor. So how do you tally scores for comedy? Actually, offered Motrey, there are three ways of doing so.
The first, he explained, is to use a process of elimination in which the referee tosses performers from either team until only one person remains (five points go to the team represented by the last comic standing).
Other heats are scored by a panel of three judges culled from the audience. And, of course, there's good, old-fashioned audience applause.
Two decades is a long time for any entertainment offering to survive in one city (there are also ComedySportz franchises in 20 other U.S. burgs, as well as in Berlin, Germany, and Manchester, England). But his company's longevity holds no surprises for Motrey.
"First of all, it's just a good product," he reasoned. "It's a consistently good show, and a lot of that is [due to] the format. The ref is controlling the game. Games can go as long or short as they need to go for the audience's enjoyment.
"That's kind of the genius of the format - if it ain't working, there's another game coming right around the corner. Or if the game is working really well, you let it keep going.
"The second thing is the talent in our company. We have an audition process. and we can choose the people we feel will best fit in. So we are able to put out a consistent product because of our talent pool."
Motrey also noted that the appeal of ComedySportz transcends generations. "We've had shows where on one side of the audience there's a group of 10-year-olds, and on the other side of the audience is a group of 65-year-olds, and in the middle of the audience there's a bachelorette party," he said. "And they're all having a great time."
One way of keeping things fit for the family trade is the "brown bag" foul. According to Motrey, any performer who crosses the line of good taste and decency is forced by the referee to wear a brown bag on his or her head.
All of which is why Motrey insisted that ComedySportz is still in its infancy here in Philadelphia.
"We're going to go for another 20 years," he proclaimed, "and 20 years after that!"
World Cafe Live, 30th and Walnut streets, 7 and 10 p.m., $25 and $22 (students), 877-985-2844, comedysportzphilly.com.