I learned this last year at a birthday party we attended right before Halloween.  It's a great way to limit the amount of candy the kids eat (although you may eat it yourselves).

 

Tell your kids about the Switch Witches.  They have green ugly teeth because they eat lots of candy and NEVER brush their teeth.  They are always looking for candy to keep their teeth so green......would you like to help?

 

If you leave out a basket of your Trick or Treat candy for the Switch Witches after Halloween, they will leave you a toy!

 

You can tell your kids how many pieces of candy they can keep, and the rest will go to the Switch Witches in exchange for a toy.  My kids were VERY excited about this last year and have already been talking about it this year!  We let them keep about 10 pieces of candy last year and gave them each a small toy from the Switch Witches.  The candy then went to my work and DH's work -- and we didn't have to fight over how much candy they wanted all the time!

 

Try it!