New Kid has this wonderful color matching puzzle from Kid O.
The reason I like it so much is that all the pieces are interchangeable so it was a puzzle he could work on it all by himself at a very young age without getting frustrated. He loved to put the pieces in over and over.
Now that he is a little older he has started (but not always) matching the three colors. Then when he gets even older (ah!) he can start matching the pieces by shade. I really like the other Kid O puzzles -- very Montessori-ish. We have the narrow to wide puzzle, which New Kid works on with quiet intent, and I think the fraction puzzle also looks great.
This post feels a bit cheesy, like I'm trying to sell something. However, this is not a sponsored post, I just think it's a fantastic puzzle.
UPDATE: Sadly, this puzzle is no longer available. (What were they thinking?) However, I found the following puzzles which look like pretty awesome substitutions: