5/ Get Spooky in a Haunted Attic
This would make an excellent concept if you are a big fan of Halloween. During the holidays, turn your attic into a haunted house-style stop for trick-or-treaters. You can fill it with a variety of scary decorations that could be reusable in many years to come.
You can even charge admission and enlist the help of friends and family dressed as ghouls and goblins. The best aspect is that you don't have to take everything down unless you want to create a new place for the rest of the year. Simply lock it and reopen it for next year when October is over.