Why not make this otherwise pagan night into an opportunity to take the gospel into dozens of homes you will never have the chance to personally visit? With every piece of candy you drop into their bag, include a gospel tract or two. Who knows the impact your efforts will make in the life of a little kid, his friends, and parents? Take advantage of the one night all year that children will come knocking at your door, asking for a treat. Plus, the parents will think it's cool that they're getting something other than straight sugar.
I like to use eye-catching tracts like the "Ticket to Heaven," "Million Dollar Bill," and cartoon tracts. Here are my favorite places online to get gospel tracts:
Yes, it's an evil holiday and I don't personally celebrate it. However, how neat would it be if someone came to Christ through a tract you gave out while kids were out trick-or-treating?