Another great indoor activity is a movie marathon. Plan your movie marathon beforehand. Will it have a theme, like alien movies or slapstick comedies? Or will each family member get to choose a favorite film? Since you're on "staycation," you could even choose movies that feature family vacations.
Then, go Hollywood for the day. Set up a red carpet in the TV room (you can use a red vinyl tablecloth). Hang up stills of classic movies and actors. Dress up as your favorite movie star or character and take "red carpet" photos of each other. To kick off the movie, toast each other with sparkling juice or cider. Settle in with lots of pillows and comfy seating. And don't forget the popcorn.