Let them dip the balloon in paint and then have them blot it onto a piece of paper. Let the children become clowns by decorating a clown's hat and taking a paper plate, cutting out the center and making a slit to the middle so that it can be easily placed around the child's neck. Use bingo markers to decorate it. You cam purchase colored cotton balls fairly inexpensive at beauty supply stores or pharmacies. Have the children practice using their pincer grasp by pulling apart each cotton ball to make them big and fluffy.
Children can decorate with stickers, sequins, glitter, etc.
Make a circus balloon. I let the children just decorate with odds and ends stickers I have left over. Attach a piece of yarn to the end. Make puppets of circus animals. Provide streamers etc and decorate the wagons, trolleys and bikes for the circus parade.