Wil Wheaton was a child actor, arguably best known for his roles in Stand By Me (1986) and Star Trek: The Next Generation. You probably know that he’s now become something of a geek overlord, not to mention the archenemy of Sheldon Cooper on TV series The Big Bang Theory. But unless you’re a member of the gaming community, you may not know that Wheaton is pretty huge in the tabletop gaming industry, thanks in part to his web series on Felicia Day’s Geek & Sundry YouTube channel.

In TableTop, which is gearing up for its fourth season, Wheaton invites various guests to sit down and play games with him. But we’re not talking Monopoly or Scrabble. TableTop dives into everything from popular party games such as Cards Against Humanity and Wits & Wagers, to role-playing games like Fiasco and Dragon Age. Guests have included game designers, actors, writers, Internet celebrities, and Wheaton’s family.

Here’s an episode where Wheaton plays Carcassonne with comedian Kumail Nanjiani, writer Nika Harper, and YouTube gaming personality Jesse Cox.

These seemingly simple videos of friends enjoying a fun diversion have caused a tabletop game boom. After each episode airs, the games played on the show benefit from major sales boosts. According to Wheaton, the effect started almost immediately, just three episodes into season one. He told Fortune:

“We started getting emails and phone calls from game shop owners and publishers because they were not prepared for the explosion of sales that they had. They wanted to know if we could let them know a little bit in advance when an episode was going to air, so that they could stock up. . . . We have looked at sales figures from the big game distributors, and it’s pretty cool. People see our show and then you just watch the spike in the sales. And for a lot of games the only reason that spike trails off is because the game sells out and they have to take time to make another printing.”

Dave Chalker, creator of the game Get Bit!, agreed that his Kickstarter-funded game benefited after appearing on the first season. “While Get Bit! definitely had its fans prior to TableTop, there’s definitely been a big boost,” he wrote on Critical Hits. “I’m sure it’s been a factor in translating it into 4 different languages for international editions (which led to a game of the year nomination for the French edition), as well as winning the Origins Award for Best Children’s, Family, or Party game.”

One game store tracked their sales of several games before and after they appeared on TableTop. The only one that didn’t see a huge spike was Settlers of Catan, which the owner attributes to the fact that Catan was already a pretty mainstream game.

Need more proof of the Wheaton Effect? Here’s an analysis of sales and BoardGameGeek ranks of the games King of Tokyo, The Resistance, and Alhambra. There are even more here.

Though the monetary sales of games are obviously a good thing for both publishers and independent game makers, Wheaton says he's just happy that more people are coming together to play games: “There is a wonderful, timeless, communal experience that is a fundamental part of who we are as social animals, of getting together in the same place to do something together.”