Seann William Scott will co-produce and take the title role in the indie pic “Gary the Tennis Coach.” O.N.C. Entertainment and GreeneStreet Films are producing. Pic will reunite Scott with his “Dude, Where’s My Car” director Danny Leiner, who has signed on. A summer start is planned. Underdog comedy centers on an overzealous high school janitor (Scott) who begins coaching a group of misfits to the Nebraska state championship.