Besides using their fingers or a paint brush, give kids another method of painting. Put a little bit of paint on a plate and use items with different shapes to make a masterpiece. In this picture, my daughter used a toilet paper tube and a plastic fruit cup to make the shapes on the paper. We also made another paper with triangle shapes. We used different sizes of cut cardstock paper folded in three and taped together to make triangles. See what other shapes you can find around your house to use. I'm sure you can find squares, rectangles, etc.
I like to frame some of the artwork my daughter makes, but when you get too much, I have another fun idea. Cut out samples and attach to blank cards to send to family and friends as greeting cards, thank you notes, etc.