Stocking Stuffers for Geeks and Nerds

I am a computer systems analyst and that means that all of my children are rather thoroughly immersed in technology. I have been giving them all hand me down computers for as long as they could sit up and face the monitor. So I am a nerd and all of my kids want to be more or less just like their Dad. They have almost everything you could imagine now, but perhaps their Dad got to play with it first. They will all get some good stuff for under the tree and I need some geek gadgets to use as stocking stuffers as well. This is the coolest thing that I have found so far, a capacitive touch stylus for drawing and writing on tablets.