I'm in Page, Arizona tonight. I have a photographer's tour of a couple slot canyons tomorrow with a Navajo guide. I wondered over to Glen Canyon dam to see what sort of night photos I could get. There was nobody around the visitor's center and it was closed. There were a couple of guards walking around on the dam and they would shine their flashlights around once in a while. I took a few exposures, mostly at about 35-45 seconds at f/11, ISO 400. The photo below shows almost the entire dam as well as some of the machinery at the base of the dam and the water flowing out the bottom. The distortions are courtesy of a 17mm lens on a full frame camera.
To show the scale, the image below is a full resolution crop of the right center of the image showing the pickup trucks parked down by the generating structures. (click on photos for larger view)