From a blog I enjoy reading...
Reformation Day Celebration
A Doorposts has a whole Reformation Night binder with studies and ideas for having a celebration with your homeschool or church group!! :D
LOTS of stuff here! WOW!!
And last but not least, while not Reformation Day specific, there is a post with a Perspective on Halloween by randy Alcorn (if you have not read any of his books, you are missing out). Done very much in a Screwtape letters type of way, this is an interesting read.