Lego. Used to play with a large castle set with 1000 pieces, when I was 8 yo. Now a days these are all specialized sets that can't be used to build anything beside the thing it was designed for.
Thought kids will enjoy. But they are more into computers. Lego recently released their Mindstorm set, with programmable servo motor which you can use to build robots.
But Arduino beat it in that game, too.
Therefore Legos are so much a thing of our generation.
