Anything that can keep and hold the attention of active boys (ages 5-12) that doesn't plug in is worth checking out. I bought a set of Castle Cards by Klutz (gotta love Klutz!) when we were studying the Middle Ages. Every now and again they rediscover them and play with nothing else for several days. This time around they even introduced little Lego characters into their play. They've been talking about pooling their money to purchase additional packs of cards so they can build "some REALLY big stuff."