What is this?

It would probably make a good background on the computer. Use comments to guess what it is. Best guess gets a gift card.

EDIT 01 Apr 2008: Only one guess??? I guess that's enough. Rhondi was pretty close! It's actually ice on the sliding glass door at the back of our house. The south side of our house was completely covered in ice the other morning... the front was perfectly clear. The temperature kept going up and down during the morning... one minute things would melt, the next it would freeze solid. I guess I'll be sending her a gift card! :)