Unshelved is a webcomic by Gene Ambaum and Bill Barnes about the staff of a public library. It's a focal point of librarian subculture as it's written from an insider point of view.
Every year for the past three years, Unshelved has hosted a contest called "Pimp My Bookcart", wherein library staffers trick out their bookcarts in outrageous ways, such as this circus-themed cart above. Click on the link to see this past year's winners.
http://www.flickr.com/photos/s-kat/sets/72157607831145211/detail/