Bubble painting! Mix food coloring in with bubbles then blow them on paper and let them pop.
Bubble Painting: Simply have the kiddos blow, and blow and blow until they have a huge pile of bubbles. Next press the paper gently into the bubbles allowing them to pop on the paper. Repeat the process with as many colors as the kids want. The end result is amazing. If you have not tried this with your kiddos yet you need to.
Mix Elmer's glue with food coloring and paint it on to any glass to make it look like seaglass when dry