I had an old-school slumber party for my 26th last year and I tried to mimic a child's party as much as possible. I know the party's today and it's last-minute, but maybe you can still use my ideas.
Food: cake, banana splits (ice cream, bananas, pineapple chunks, strawberry sauce, chocolate syrup, caramel syrup, sprinkles, whipped cream, cherries, nuts), popcorn for a movie, chips & dip, soda pop, and lots of candy
Favors: lip gloss, hair bands, light-up bracelets, stickers
Activities: MASH (see picture), Twister, fashion shoot (do manicures and hair, then take photos), movie, presents
Breakfast: pancakes or waffles and juice
Hopefully this helps you even though it's tonight!!