Some of the girlfriends I used to go out with, now give me nightmares, so I am not so sure I would want to do what this guy did, in my bedroom, as my wife might object.
http://selcouth.com/ceiling/
You are going to need the Rasterbator, if you want to do this yourself.
Instructions here...
http://homokaasu.org/rasterbator/
Now there are a few blank walls at work, and home that would definitely be suitable, but which girlfriend should I chose ?
Have fun