DIY crafts for the home easy. DIY - Sharpie Coasters, ceramic tiles (free or very inexpensive at any home store center), rubbing alcohol added with a straw or eyedropper, (for the colors to mix) -- Great inexpensive gifts!
Soap Foam Printing: Brilliant, Messy Art for Kids - Fireflies and Mud Pies
Choosing colors & painting water over them. Watching the water smooth them down and colors bleed together. Tissue paper art is relaxing and suitable for any age level. It's perfect on it's own as a process art activity or as a colorful first step. Tissue paper painting is also known as a tissue paper bleed.