Ohhh, I didn't see that YOU are supposed to design the product. I was thinking you were designing a logo for it. But something that runs off a USB port? Maybe a fan computer fan? It would be useful if all the other ports for fans were used by something else. Or possibly that solar charger. That would be pretty cool. Just leave it in the sun for a little while then it runs for hours. But that would be hard to create, even a solar panel that size wouln't hold much.
I don't know, maybe (hopefully) someone has some other ideas.