In an age of video games and noisy high-tech toys, Brainwright's Manifold is a very rare find. I got truly delighted by the idea of folding little papers into origami, trying to achieve some easy to understand task. The goal is simple - you start with an 8x8 paper, which has 16 black, 16 white, and 32 empty squares printed on its front. You must make several folds, so that it ends up as a 4x4 paper with all black squares on one side and all white squares on the other.
For under $10 I was able to get a set of 100 puzzles, many of them quite challenging, which translates into several hours of gameplay. The difficulty of the puzzles gradually increases, which makes Manifold appropriate for all ages. Despite my highly positive impressions, I have to point out several (minor) flaws. First - the paper, despite being high quality and glossy, may not be the best choice for making origami with it. Second - there is too much empty space left at the edges of the papers, which may get in the way when one needs to make many folds in one puzzle. Finally - once solved, the papers naturally show the folds applied on them, so they may not be ideal for solving more than once. Despite these few gripes, Manifold receives my highest recommendations.
If you want to try some sample puzzles from the set before buying it, you can print them from this PAGE.