Well if you have Windows Plus installed and you press CTRL + Space, it closes all your windows to do with MSN and Hides them.
At first, I thought it was a bug until I looked into it. When in fact, it just allows you to hide anything to do with MSN :D
To get it back up, you click on an icon which looks like a hard drive and all the windows will open :D
Icon:
http://jewbear.net/img/1224422924216.png
Never knew it was a feature :P

