We drew and painted worms one rainy day - trying out markers and watercolour. We drew noses and mouths another day, and worked in our sketchbooks.
We created plasticine masks with some p-mache, and mini clay creature heads that we painted and balanced on skewers and made mini pets for. We did some cute group paintings and some silly, impromptu stop-motion animations as well.
And we created our own Mr. Moody's. Ours give us a wide and entertaining range of often surprising expressions, as we invested in creating unique drawings for the features. Our first Mr. Moody was a collaboration much like the 'exquisite corpse' game the Surrealists liked to do where each person was given a part to draw, but did not know what the previous person had drawn - resulting in a surprising combination of features. We even had an opportunity to use Mr. Moody to gauge the mood in the studio when a discussion got over-excited...Mr.Moody's can be made into a fun and simple animation project too...rotating and even swapping out features for quick changes.
See this link for a simple how-to: http://www.mrprintables.com/learning-about-emotions.html