A quick purpose idea this time. Gather items that are all the same shape. Lots of different sizes but the same shape. The easiest shape to gather is the circle.
We paint with them. Encourage kids to experiment. What different kinds of designs can they make with the circles.
If you don't want to use paint, try stamp pads instead.
We've made faces, flowers, and just lots and lots of circles.
(Need stamp pads? The ones I love are from Discount School Supply. The ink is washable. Really! It washes off with soap; hands are completely clean.)