My first thought was that fingerpainting is a great sensory activity. I mean, after all, he LOVES to color with whiteboard markers in my classroom and Magic markers on butcher paper. So, out come the fingerpaints and several large sheets of paper. Eli's Aunt Joy came over to help me, since, after all, art is her specialty. We put on old clothes, except for Eli, who was content in just his pull ups (it was about 85 degrees out), and went onto our porch.
I put Eli's hand into the paint and showed him how to get it on the paper.
He wasn't thrilled at first about having the paint on his fingers. In fact, he used his "canvas" as a napkin most of the times that I put paint on his hands. Joy and I were able to keep him going long enough for him to get the idea of the activity and spread the paint a little on his own.
And while he did decide that he had enough of the fingerpainting after about 15 or 20 minutes, he did seem to enjoy himself (ok, mostly he was laughing because he was trying to use our clothes as a napkin...). But his "art" came out cool enough to make nice framed gifts for family : ).