Credit: Jason LaVeris/FilmMagic; Michael Buckner/Getty

Game on, boys! While Texas Hold 'Em may entice Hollywood card players to come together for game night, it's XBox that proves to be the It activity for Will Arnett, Justin Theroux and their famous friends. A source tells Us Weekly Amy Poehler's ex, 43, teamed up with Theroux, 42, Jason Sudeikis, 38, and Jerry O'Connell, 39, to create a "secret XBox clique" where the men challenge each other with XBox One games.

The best part of the famous friends' exclusive sessions: They always take place after midnight! "Will created the group," a source tells Us of Arnett, a dad of two who split from Parks and Recreation actress/comedienne Poehler in September 2012.

In the wee hours, the celebs -- whose significant others include Jennifer Aniston, Olivia Wilde and Rebecca Romijn -- challenge each other online from their respective home consoles.

And as the old saying goes, in this gamers' club, boys will be boys. "[Will] sometimes messages Justin to see if he wants to play," the source continues of Aniston's fiance. "Then they round up the others and do multiplayer sessions."