So this year I decided to go quick, easy, and lo-fi as a USB drive:
To make a thumb drive/USB key, I just took a cardboard box, spray painted it black, and glued on some gold-colored paper. Super simple and easy to do. Then I cut out a curve for my head.
I made the mask using digital plans I bought from wintercroft.com. Once I had the materials, it took me a couple hours and was lots of fun. It was like a super-simple version of this big head costume.
If you wanted easy freedom of movement, you could also just wear the USB part on your head: