Lots of gadgets are made for the USB PORT nowadays, lamps, ventilators and small vacuum cleaners.
Why don't you try to make something funny yourself, using the USB?
This instructable very low tech, demanding your inventor and designer skills more than electronics. And no programming!
We will take one of these gadgets as a starting point (they are very cheap, 1-2 euro's) and make something experimental out of it, demonstrating the paper button principle. It is like having a very superficial dream compared to working with programmable chips and sensors and complex wiring jobs.
We use the principle of the paper button:
( see this instructable: http://www.instructables.com/id/Paper-button/ )
Step 1: Tools
A screwdriver, scissors, a cutter, glue, tape, maybe a soldering device comes in handy too.
for the button: paper, aluminum foil, and electrical wires.
Paper is a rich material, there are a lot of different papers and quality of papers, for the buttons we use light pliable paper, but for a base you can use heavier more stiff papers. I like the Japanese papers very much, but also used paper, printed paper, paper with texture on it. Also the paper which has been in the sun, yellow is nice. Paper is very much wabi-sabi for me...
And we start with a gadget, but once you discover the principle, you can use old USB cables from a mouse, or whatever.
What you don't need is batteries!