Occasionally I'll see something strikingly clever.  It's not often, but..

In my apartment building, in the basement, there is a sign.

The sign is much like other signs in the building, it reads:
"VANDALISM HURT US ALL
THANK YOU" etc etc it's not important, the important part is the first line

The thing that's clever is that someone, in pen, wrote an S after the word "Hurt"

It really makes you think.