Lets Make a Deal
You will need:

Three boxes with holes cut in the back and the bottoms, small paper sacks, and lots of different sized prizes.

Lets Make A Deal, is played very much like the game show on TV.  Call up one of the Children and ask them a question.  If they answer the question correctly, give them a brown paper sack with a prize inside (they are not allowed to look inside the sack).  They then have the option of keeping the sack, or giving it away for what is behind box # 1, box # 2, or box # 3.  (Each box has a different prize under it.  Some of them silly, like a can of dog food, and some of them nice.)  To make it exciting, if a child chooses box # 2, show them what they could have gotten if they would have kept the sack or picked boxes 1 or 3 before you show them what is behind their box.  Another fun thing to do is to try and talk them out of their box by offering something else before looking under their box.