Astronaut Pudding! Give each girl a ziplock bag and let them scoop 1tbsp. instant pudding powder. Then they add 1/4 c. milk, seal the bag and squish away. Once it forms pudding, they snip off the corner of the bag and have a mess-free snack! My troop loved teaching this to other scouts.
Take a ticket stub, plane ticket or whatever to kinkos, have them blow it up, print it on fabric transfer material to make a pillow. This would be so fun for big trips or things done as a couple (honeymoon tix, first concert together, etc)