This doesn't really answer the question but if you videotape a game and fast forward between every play, commercial and halftime, it takes about 40 minutes. Obviously there's a lot less action than that however.
I dont know, but what I do know is, If my bets in front, its an eternity. If its trailing, the clock just wizzes by. The same thing with Horses, when your nags in front, they seem to run another 2 furlongs in the straight.