We gave my nephews this video microscope for Christmas. It was a big hit. It lets you zoom way in on things and then take digital pictures which you can download onto a computer. They had fun zooming in on things like skin, hair, and carpet and being simultaneously amazed/grossed out.
It's list price is $80 but Amazon is selling it right for $18. It's a great deal. I know everyone's pretty much all shopped out by now, but it might be worth snagging now and hiding away for your science-loving kid's birthday.