One way to avoid leftover candy is to avoid candy altogether. Says Judi:
No candy at our house. Stickers or doodads from Oriental Trading instead! Anything leftover goes into the arts and crafts bin for use throughout the year.
Bonnie and Gina mentioned this particular hack in earlier comments, and Mark suggested handing out mini Play Doh canisters. I like the idea (especially the Play Doh) but I wonder how much of that stuff contributes to our collective junk pile? But then, is junk inside the kid any better? Hmmm.
Another thing to add to the list of worries: many cheap toys may contain lead. (When I posted that notice last year, it didn't have the impact it has on me now, in the wake of the massive toy recalls.)
Related: Can we call it "regoodie-ing"?
More: Easy Halloween tips