Working on your laptop in the dark can strain your eyes. But sometimes you might need to work in a dark room because others are resting. In that case, a cheap USB light will solve the problem. Just plug the light into any free USB port and switch it on, and soon you'll be able to see well enough to type in the dark. USB lights can be used when you need a light to read by, but there's no convenient location to plug a light in. The best USB lights produce enough light to illuminate an entire room. Best of all, they're small and can be carried anywhere.