Balloon printing is such an easy way to introduce printmaking to little kids. We only inflated the balloons a little, to make them a good size for the kids to hold (and reduce the chance of them bursting mid-print). We mixed primary colours and white paint in ice-cream contains for them to dip into, and offered a range of kitchen sponges cut into squares, triangles and rectangles. The kids experimented with squishing, rolling and dragging the balloons, pressing and wiping the sponges and scratching back into their painting with their fingers.
We also had a freeform threading and collaging table. Invitations to play were set up with plastic safety needles, kitchen string and tinker trays filled with pompoms, cut up straws, pipe cleaners, coloured pasta and beads. We also put out box lids, cardboard, a stack scrap paper (left over paintings from earlier sessions), metallic crepe-paper (oh, so pretty!), patty pans and a heap of scissors and glue. The kids really enjoyed the cutting and gluing (especially my kids, who could glue all day).