Since there was no way I could get a picture of it, here's my crappy five-minute Photoshop representation. The curved horizon is supposed to imitate a wide angle lens, since this thing was so huge. Also, you can see where I painted in the spectrum at the bottom.
I did some Googling, and discovered that the ring of light is called a corona and is actually quite common with both the moon and the sun. However, I never found a picture that showed a corona as big or as bright as the one I saw. The really cool part, though, is the spectrum I saw. It's called a moon bow, and is really rare. Last night, only about ten minutes passed from the time we could make out the spectrum until it had faded away completely.
Basically, I figure that what I saw last night is probably a once-in-a-lifetime thing, which I think is pretty damn cool. :-)