An M7-class solar flare from Sunspot 696 hurled a coronal mass ejection toward Earth that sparked extremely bright aurora borealis over much of North America during the early morning hours of November 8, 2004.
I'm not sure if the blue was actually there, or if it was a result of my post-processing on the image. But the red/pink was definitely visible. That was the only time I've ever been able to discern any color besides green in the aurora with the unaided eye. Usually the camera can pick up those reds and purples when I can't see them, but this time I actually saw the red. It was beautiful.