With ds it was the Thomas the Train popup playhouse train.. That was a hit with dh too since he didnt have to put it together, it just popped up into shape out of the box..
With dh it was the heelys i got him.. Hope he doesnt break his neck trying those things.. Saw some little kids with the heely things in disney world and thought they looked cool and found them in a mens size 11 for him when amazon had that shoe sale in november

he loves them.