Balloon painting! I did this on the first day in my Creative Expressions in Play course (in Spring 2010) and it was so much fun, so I would imagine that it'd be as equally, if not more, fun for Pre-K classes!
Memory Game Put three shapes on a tray, cover them with a cloth, and take one away. Uncover it and children guess which shape is missing. Another way to play is to have the children show what they saw using their own set of attribute block shapes or draw what they saw.