Check out this pen projector concept by Edgar Navarro, where the finished product is known as the Portable Pen Projector. It relies on an LED lamp system to throw images onto a suitable surface, making this less prone to expensive lamp replacements found on traditional projectors. Apart from that, rings on the pen itself are touch sensitive and can be used to adjust resolution and focus. Need an impromptu projection stand? Just take the pen cap off and let it stand on the table. Guess this is one design where we will just have to wait until technology catches up with the idea.