Make a rainbow! Good craft for working on cutting skills. Also consider having the kids pull apart the cotton balls first (using those pincers!) for a little more fine motor focus.
art activities for kids with rolling yarn Bet You could do this with dried/used corn cobs and toss it all out when done! - pgh
abstract art with droppers, liquid water colors, and paper towels - beautiful and great for fine motor development
Shaving Cream Painting
Creating Your Own Pictorial Family Tree Using Inexpensive Frames, A Little Paint and A Photocopier.