Perhaps purchase a polaroid camera and try this idea (instead of a photobooth or as a wedding favor). DIY Wedding Table Decoration Ideas - Novel Guest Book - Click Pic for 46 Easy DIY Wedding Decorations
A photo guest book - polaroid and washi tape! Get a cheap but cute polaroid camera, a blank notebook, and washi tape in your chosen colors. Have guests take photos and then leave a message underneath. Love this, but polaroid film is expensive and rare!