4-D Cityscape New York City Puzzle for his birthday in late August and he's been diligently working away at it. He was thrilled to finally complete it last weekend (with some help from Grandma!).
It was a great gift because he loves New York, buildings, and miniatures. He had a wonderful time working on it and he really learned the layout of the city from the tactile process of laboriously fitting the pieces together.
Many children's museums and science museums have hands-on exhibits to foster tactile learning; such exhibits often seem to be less than effective or engaging for N. But I think the difference with this puzzle is that "fourth dimension," time. The time it took him to put the puzzle together and the time he has to come back to it again and again make it deeply engaging and productive as a learning experience.
Bonus reading: Here's an interesting meditation on the role of time in learning, by Lori at Camp Creek Blog.