A music center can be a perfect ways for preschoolers to express their creativity. Place some noise-making items in a box at this center, like an oatmeal can filled with beans or a small plastic kazoo. You can also wrap a few rubber bands around a tissue box for a makeshift guitar. Let preschoolers put together their own band and create sounds for their own songs.
An art center can include a number of craft materials for preschoolers. Fill a bucket with glue, cotton balls, Popsicle sticks, pipe cleaners, old paper towel rolls and anything else you have on hand. Tell preschoolers to use the items to make their own robot, which they can decorate with markers and crayons.
Reading may not sound like a Fun Day activity, but you can kick the subject up a notch for Fun Day. Have some sheets of paper at the reading center and let preschoolers draw pictures from their favorite storybooks, or from a book you've been reading in class. You can staple the pages together so kids have their own homemade picture book.
A dress up center can be fun for both girl and boy students, giving the kids a place to let their imaginations loose. Place some costume pieces, like tutus, crowns and cowboy hats, in a box at the center of the group of desks. Let kids at this center design their own costumes, then come up with a skit to perform for the other students.