Create a collage. Simply choose a subject, it could be as simple as just eyes or as unique as places they'd like to go. Just gather up a variety of magazines, a pair of safety scissors, a glue stick and a heavy weight paper for their canvas.
Supply your kids with materials, and they'll do the rest. Give them empty boxes, toilet paper tubes, old magazines, and inexpensive craft sticks, along with some decorative materials (sequins, glitter, feathers, etc. ) and glue, and they'll be able to come up with all kinds of exotic creations.
Make silly putty. Use liquid fabric starch & Elmer's glue (cheap stuff doesn't work). Mix in an old bowl or washed out throw away container. Have kids wear old clothes & cover table.