Forget the Spray Paint
One of my husband's coworkers told him about a nifty website called Wonderful Graffiti. You can design your own graffiti for walls, doors, bookcases. Here's a photo someone sent them to give you an example: You can choose from their designs or design your own and they even offer suggested quotes for your library in case you are having difficulty coming up with something! The letters are made of thin vinyl with an adhesive on them to make them stick. We use this type of lettering for signs where I work. I can attest that it is durable and easy to apply. However, if you make a mistake while sticking it down, you're SOL. You can't remove it and re-stick it. Of course, if you are the crafty type you could make your own stencil and use paint. While I tend to be a crafty gal, I draw the line at too much trouble. So I will probably end up desigining some grafitti. The hard part is deciding what I want it to say and where I want to stick it. So many possibilities.