This is a little delayed, but I visited the Didax booth last week at NCTM, and found some cool toys. What I took home was a small set of Geofix tiles - a set of interlocking polygons of equal edge length, which can connect to form Platonic and Archimedean solids, as well as stuff like mushrooms and snails:
As soon as I got home and showed these to my kids, they sat on the floor playing with them (and fighting over them) for a long while. My 9-year old made the snail.
Anyone can design anything in 3D! www.3dvinci.net