A youth pastor or youth leader offers $20 to any person in the group who will let him break two eggs over their head. Of course young people will usually do anything to get a few extra dollars!
After you choose the person you ask them to come up in front of the group while the eggs are broken over his head. (Have a towel nearby!) Up to this point you have not given him the $20 (have it tucked just outside your pocket where it can be seen) After the eggs are broken tell him that he must think you are crazy to give your $20 away to someone who was foolish enough to believe you would actually do that. Really emphasise how silly the person was to let someone trick them into believing they would actually get rewarded for doing something so foolish.
Then tell your group that this is just how Satan is. He promises you all kinds of good things but in the end your really the loser. Then to really bring out the message, say Satan is unlike Jesus. Jesus KEEPS ALL HIS PROMISES. Then hand the $20 over to person!