I see quite a few wooden signs with the letters turned all which ways and mixed up fonts. Here's one that I pass every day:
Anyone else catch some of these in the wild?
I started taking photos of inverted and flipped letters a few years ago, but gave up when I realised just how often this happens. My favourite example is in Brompton Oratory in London: there is a monumental text running around the inside of the dome in brass letters that must be at least 3ft high (it is difficult to judge, because it is so far up). One of the Xs is upside down.
Sign in Rome.
http://socialdesignzine.aiapnet.it/images/cartello.jpg
"For turists: no parking here please.
For everybody else: you pissed me off.
Sunday open."
NoWindows
http://homepage.mac.com/juggle5/fun/NoWindows.jpg
More bicycle lane fun:
http://www.geocities.com/fredpipes/cyclelanes/cyclelane4.html
Link via This Is Broken. You can usually find some great oddball signs and completely distressing instructions over there. This is one of my favorites:
http://www.goodexperience.com/broken/i/04/04/union_station-s.jpg
AH AH!
Thanks for the link, this is my favorite:
http://www.goodexperience.com/broken/i/03/11/whichway.s.jpg 
Captured from web.archive.org on 2 Jan 2011. view this capture