I realised yesterday that someone in the UK is driving about with the number plate M1 AOW. That plate will be worth a few thou$ands!
The licencing authorities refuse to release number plates which could/would be offensive, such as PEN 1S, but a canny Scotsman eluded them by ordering PI55 AFF. (AFF is a colloquialism for "off" in parts of Scotland, so you can see what the number plate would mean to many when the 55 looks like SS)