IBM did some creative (and useful!) things with the early Thinkpads. Remember the 755CD/V? You could pull the backlight off the LCD and strap the laptop to an overhead projector.
Awesome, I would never have tought that this is/was an actual product! We tried to do something like this as teenagers with an old (normal) LCD, but some ribbon-cables were in the way. Still, there are people building projectors themselves using that method.
