If you use or can install a linux machine, you might find GCompris as valuable resource. (it has packages for Windows too, but not as feature-reach).

We have also found extremely attractive the "find the clue" type of game, where kids were supposed to find the next small clues hidden in the house (pieces of paper with instructions), based in indications found in the previous ones. The reward at the end was always a source of fun.

However, the most entertaining toys are ones for outside play: kites, bow-and-arrow, climbing walls, diy catapults and the list can continue.