I’m pretty sure this will only work with smaller children.  They are less suspicious of vague “prize” promises.  Plus, I’ve tried this at camp before and know that the older kids see this as torture.  Although, it may be all in how you present it.

Yesterday, I was in First Grade, and we needed to be in the hallway for an extended period of time.  Feeling very outnumbered, I decided to implement the quiet game.  It helps to build up with an excited voice:  “Hey, have you guys ever played, the QUIET GAME??  Wanna play??”  Basically, they can’t talk, or whisper, or gesture too big for a certain amount of time.  I set it for the whole time we were in the hallway.  Then, whoever violates the rules doesn’t get a prize.  Of course, you don’t tell them what the prize is beforehand, just incase you get a few self-righteous students who “don’t LIKE that…”  I also decided not to tell them flat out who had not earned the prizes as I caught them talking, so they thought maybe I would give them a second chance and clean up their act.  Otherwise, once they know they’re out of it, they’re more likely to not care and just go nuts, slowly dissolving the whole game.

That was the quietest I’ve ever heard that group of students!  All 21 of them!  Of course, over use of the quiet game will also make it less effective, so be careful not to run to it too quickly.

Prizes can vary, but should be something super small so that you’re not making it too big a deal (a ticket, a sticker, a pencil eraser, etc.).  And prizes should be given rather quickly from the stopping point so that students can associate the prize with the behavior.