Outdoor Clamp Light —
I used two of these lamps with 60W equivalent compact fluorescent bulbs for a 10x10 vendor tent at a music festival. Attachment to the tent frame was simple, although a little duct tape was useful in stabilizing the clamp onto the square frame tubes.
Two lamps ended up being too bright, so we only turned on one in the end.
An inexpensive and completely satisfactory product for this application.