My SIL got something called Sphero for my little brother. Not sure what it is, but it's supposedly all the rage. (It's some sort of ball that has apps, but I'm not sure what all it does).
I got my nephew one of those home planetarium projectors a few years ago. Not sure if that's something he would be interested in since he's crossed the telescope off his list.
This is why people should make a wish list at Amazon (or somewhere) with things in various price ranges they can refer people to