Our son is getting Lego Mindstorms, which he has asked for for 3 years and I finally feel confident he can do (he is just 8, but a building fiend). Our DS is getting a fairy house I built.

One suggestion for games is Blokus. This is a game you can play with your kids and everyone will really enjoy it - but it is challenging. My son can beat me even when I am trying my hardest, and even my DD who is 4 can play and have fun.