Tea Partyin'
I’m stealing the link to this Teabonics flickr group from Warren Ellis, but it’s just too good not to spread around*:
The saddest thing about this, to me at least, is that someone took the time to pencil in some perfectly straight lines before screwing up nearly every other aspect of their sign.
As you might discern, my favourites are the ones that imply something the sign-holder never intended.