My wife and I were in a dark sky area in the northern lower peninsula of Michigan this weekend.  We saw faint fingers of light off to the north around 11:30 PM.  They were bright enough to be unmistakable, but there was very little color.  As the night wore on, the "fingers" got longer and more distinct.  We thought they might be auroral - from their position they couldn't be any other optical effects we were familiar with.

Checking spaceweather, though, there was a little bit of solar wind that evening, causing auroras in the northern and southern hemispheres.  An observer in Wisconsin got it on film:

http://www.spaceweather.com/aurora/images2007/14jul07/Wilder1.jpg 

http://www.spaceweather.com/aurora/images2007/14jul07/Wilder4.jpg