As a follow up to my post on ring lights, here you have some more interesting resources on the topic.
Here is a video from famed photographer Jill Greenberg. She uses the ring light too and you even see a scene in this video where she is using it while photographing a bear.
Here you see David LaChapelle at work. He also uses ring flashes in some of his pictures. At about minute 3:30 you will see him working with one