Some months ago, Katie received a small set of Magformers as a present. I was immediately impressed with the way these things were built, and we spent a few days playing with them. However, the set that she got only contained 14 pieces (8 triangles and 6 squares), and so after building pretty much everything that could be built, we put it away for a while.
At our large Thanksgiving gathering last week, someone had brought this set of Magformers that contains 62 pieces, and I saw what one can really do with these things. During the four days, kids of literally all ages (about 2-45) spent hours playing with them, making a myriad of structures. Some were very mathematical, while others were more artistic in nature. I was extremely impressed when a ten year old girl made this:
Addendum: I just found out that she also made this: