Krusty the Clown.
Not a movie but still the funniest gambler ever.....
Krusty's accountant : "Let me get this straight Krusty. You took all the money you made and bet it against the Globetrotters????
Krusty :"I thought they were due! The game was fixed! The Globetrotters used a ladder for Pete's sake! C'mon! He's just holding out the ball, take it!!