Extraordinary set of 2 long lasting flashes light up the entire sky.

While watching a movie early in the AM, I was distracted by two separate extraordinary flashes of light in the sky.  The Color of the flashes as viewed from inside my house was a blue/green to purple.  Each flash lasted for about 2 seconds.  (one one-thousand, two one-thousand)  This was a cold, lightly clouded evening.  The color, duration, and circumstances were not like lightening, and typicaly "fireballs and meteors don't seem to come in pairs.
 Each flash was about 1 minute apart.  About 5 minutes after the flashes, my roomate came home from work and described seeing the same thing as he was driving home.  The intensity, duration and color of the flashes were suprising to my roomate as well.  The flash lit up the entire sky in our area.