I just love this little dohickey! Seriously - there are a million people who cross your path but you never have time to get a card to them (or you don't have their address, either!). I made a couple dozen of these to keep in my truck. I hand them out in drive-thru lanes, give them to the mail carrier, hand them out to an unexpected encounter of a friend, and in the waiting rooms where I always seem to be.
The only trick to this fold is learning how to line up the light bases so they fit together properly.