First of all, make sure your USB hub has a DC-in jack. If it doesn't, you can still just plug the hub into a USB port on your computer to power it. You may have the original power supply that came with the hub. The plug should fit into the jack and supply 5 volts of DC power. If you have a polarity indicator (it shows whether the center is positive or negative) on the hub, make sure it matches the polarity of the power supply. If not, just try it out and see if the light on the hub comes on. If you are worried about possibly burning out your hub, then don't try this instructable. I'm assuming that you are using an old hub that you have no other use for and will not miss it if you break it. All that said, I've never burned anything out with only 5 volts just by testing it.
Next, go to the Dollar Store and buy a few computer lights. These are the kind that plug into a USB port and are mounted on the end of a 12 - 14 inch flexible stalk. you can get as many as you have USB ports on the hub, if you wish.
Then just plug the lights into the ports on the hub and plug in the power to the hub. The lights come on and Bob's your uncle!
I mounted some old hard drive magnets to the bottom of the hub with epoxy. This lets me attach the whole assembly to my computer's steel case. This won't work if you have an aluminum case.
I found these lights to be bright enough to light my keyboard when the room is dark - essential for those late night gaming sessions. Enjoy!