Our neighbors are super big into holiday decorations. We are currently in the throws of Halloween decorating in my neighborhood. That translates into: "We are now surrounded by a large number of skeletons, gravestones, spiders, and strobe lights." While I enjoy this, my small princesses don't enjoy it so much. It's a bit scary for a 4 year old and 30 year old mother (who happens to look 23, by the way).
Since we can't decorate as scarily as our neighbors, we have done a few Halloween crafts / projects with Emma and Brooklyn to help decorate our house for Halloween (or for you "Jesus condemns all things Halloween" folks, you can call it "fall happiness decorations"). They're both pretty easy, and they make fun little mementos. Or at least, fun blog posts.
Ghosts: paint the kids' feet with white paint. Turn the page upside down and paint eyes. You now have ghosts.
Mr. Potato Head Pumpkin: Get a pumpkin and put Mr. Potato Head accessories on it.