I was going to hold off posting any napkin sketches, thinking it might be well to "save" them for the SAF event, but as it won't be the first any of us have shared, here's one of mine. More at http://www.flickr.com/photos/fuzzyimagearts/
This is the ceiling of King Street Station, being restored after removal of the dropped ceiling that hid its grandeur for many years. The dropped lighting is still there though! Sketched on location (of course).