How much would it cost to buy a bunch of hillbilly teeth and distribute them at the gate? Can you imagine the hilarity if every shot of TV shot of the Arrowhead crowd looked like this?
Or, make a couple of huge signs with 'Cheer' on one side and 'Stop' on the other and put them in each end zone. You know, since we're too dumb to know when to cheer and stuff. For extra credit, have two guys wearing suits, sunglasses and earpieces flip the signs as appropriate.