"Tsumiki" chalk building blocks by a Japanese company. This is such a cool idea for kids to design there toy with chalk and then redo it over and over again. I bet you could chalkboard paint wooden blocks and DIY.
cardboard tubes + box = hours of fun! We pieced together TP and paper towel tubes. Used marbles. The kiddo loved it and even still pulls it out to roll the marbles into a dump truck. He wont' let me toss any cardboard tubes now.
Attention all my preschool teacher friends - Fish craft! Thanks to magnets hidden under the lid, this goldfish shimmies, quivers, and floats in its jam-jar bowl just like the real thing. way better then real fish!