Make It a Movie Night
Kick the usual movie snacks up a notch with a popcorn bar. Pop a big bag of plain kernels, put them into a large bowl, then set out smaller bowls with different mix-ins such as M&M's and nuts. Let kids decorate paper bags to hold their custom popcorn creations.
Make It a Backyard Campout
Pitch a tent, fire up the grill for hot dogs and s'mores and create a nature-themed scavenger hunt the kids can do right in your yard. You could even print out ghost stories that hte kids read to one another--choose mild ones at americanfolklore.net.
Make It a DIY Pizza Fest
Make It a Nighttime Olympics
All you need are bendy glow sticks and sporty supplies you probably have around the house. Use the sticks to light up an obstacle course, or stuff a tiny one into a Wiffle ball for a game of "dark baseball." The possibilities are endless!
Make It a Spa Party
You already own the polish and remover, so creating an at-home spa for the girls is virtually free. They can paint one another's nails, do a friend's hair and play dress-up. For easier cleanup, put down a disposable tablecloth before partygoers start their manicures, and lend them clothing and accessories that you don't mind seeing damaged. Serve pink lemonade with paper straws to go with the girlie theme.