When someone takes a lot longer than the time they said. A football game consists of four, 15-minute quarters but because the clock stops a lot, the game is a lot longer than 45 minutes. So when someone tells you they'll be 20 minutes, it's 20 minutes football time.
Bob: Jim said he was going to be 20 minutes before he shows up.
Bill: Yeah but, he works in football time so he'll be about 40 minutes.