My kids are pretty young so we 
usually let them trick-or-treat up and down two streets and then we are done. This year we let them do four streets. You wouldn't think that would add up to much, but my goodness they got a lot of candy!! Their buckets were full. I am sneaking as much as I can to save their teeth from all that sugar (aren't I a loving mother?). But what else can you do with the candy? Here are some good ideas:
1. The 
Switch Witch. We have some friends that tell their kids they can either keep their candy 
or pick out 10 pieces and then leave the rest in a bag on the porch on Halloween night. During the night the Switch Witch takes the bag of candy, and in exchange she leaves a special gift such as a board game or an action figure set that they've always wanted. For a fun and elaborate story to excite them, see the story at the bottom of this list. You can change it as needed to fit how you play the Switch Witch, of course. Then you (ahem, the witch) can take that candy to do #2:
2. Sell your candy back to a dentists office. Yup. Some dentists will buy back Halloween candy by the pound. Visit the 
Halloween Candy Buy Back program to find a participating dentist near you. The candy is then sent to the US Military deployed in harms way. Some dentists will pay you cash (~$1 a pound), some will pay with coupons (partnered with other businesses) or free services. Check it out.
3. I have heard of people using the candy to make gifts or decorations for Christmas
                  -make wreaths
                  -gingerbread houses
                  -ornaments
                  -stockings 
4. You can put it in a plastic baggie or food saver bag and put it in the freezer to save it for other holidays like Valentines day or Easter.
5. Save it for your kids school parties or birthday parties
                     -Gift bags
                     -Pinatas
                     -Prizes
6. Make a Thanksgiving or Christmas advent calendar with it.
7. Donate it to a nursing home or children's home or other place in need of a little Halloween cheer. 
8. Bake with it. 
The Switch Witch Story
The Switch Witch lives in Hallow Heights which is a little island in  the sky by the moon. The Switch Witch loves candy.  All witches love  candy, but the Switch Witch loves candy the most and she has the biggest  candy stash of all the witches.  Do you know how the Switch Witch gets  her gigantic candy stash?  The Switch Witch gathers most of her candy  for herself and all the witches and cats on Halloween night. (Did you  know that witches’ cats love candy too? They only eat milk chocolate  though as it has delicious milk in it! –this is true only for witches’  cats though!).  So, here is how the Switch Witch gets her candy: late  Halloween night, when all the children are sleeping, she visits the  houses of children who choose to switch their candy for a toy. How does  she know which ones are switching their candy in? A child puts a piece  of candy on the door (of their room or house) to let her know that they  want to switch.  The Switch Witch flies from building to building on her  broom, with her black cat Corn (as in Candy Corn) on the back. They  come in through a window. They fly in through the window with magic- the  window does not need to be open.  She takes all the candy the child  puts out and puts it into a sac that Corn holds open for her in his  mouth.  Then she ties the candy bag to the end of the broom.  She takes  out a shiny black bag that is full of toys. She leaves one toy for the  child to thank them for the candy.  Then she leaves just as quickly as  she came: on her broom, out to visit other children and perform more  switches. By early morning, she and Corn return home to Hallow Heights  where she sorts all the candy into large glass jars. That night, all the  other witches come to visit and the Switch Witch doles out the candy  they want.  They eat their candy with her, share stories of Halloween,  hear about what toys she brought to the children and come back night  after night for a treat.  You know how most pictures of witches are  flying near the moon?  That’s because they are on their way to Hallow  Heights to visit the Switch Witch and share in her gigantic candy  stash.  By next Halloween, the Switch Witch has run out of candy and  goes back out to do her switches.
(Seen on A Child Grows in Brooklyn: http://www.achildgrows.com/2009/10/21/the-switch-witch-what-to-do-with-halloween-candy/) 
Happy Halloween!