I'm regularly reminded of that one at work. Probably 5-6 years ago the toilets on one of the main offices were being refurbished, they did the ladies first and then started on the gents.
Whilst the work was in progress the toilet was closed and you were supposed to use one of the other toilets which usually meant having to walk further.
Being a company in a vastly male dominated industry females are very much in the minority, so I guess a few of the lazier blokes were using the freshly refurbed ladies toilet instead as, before long, a 'temporary' handwritten sign appeared on the door that just said "Ladies Only".
At the time there was nothing more than a temptation to add "Do you think I'm attractive?" to the bottom of the sign, however as no-one would have got it there wasn't a lot of point so I refrained.
For some reason once the work on the gents finished the handwritten sign wasn't removed.
Some time later someone from the services/cleaning company who looks after the site with access to a laminator must have noticed it, and as we all know people with access to a laminator like to make laminated signs for *EVERYTHING*.
Presumably they saw this faded handwritten sign and thought "I can tidy that up" so now we have a nicely printed and laminated sign that still says "Ladies Only" and it'll be there forever because it looks official and purposeful.
Due to the thread here I'm probably the only person in the company who noticed the sign enough to realise how and why it's come to be there in it's current state.