Oh, your office decor is great, but why in the world would I need a doctor?! 
My “office” pictures
South wall East wall North wallWest wall West wall
Conan, what is Best In Life?
Crushing your water bottles before throwing them in the trash,
Emptying them before you,
Hearing the lamentation of the women.
That’s all we got in public. The devs have drawings all over the walls in their rooms and windows, but no actual signs, motivational or otherwise.
Dad, I didn’t know you bought the despair.com posters! When did you get them?
Has anyone recognized catbus?
The shop I work in has this one hanging under the clock.
The head mechanic at a construction company I used to work for had a sign with a hand-drawn guy holding his head in despair. The caption:
For some wallpapers for your desktop, try these (shameless plug, but no money involved).
At the radio station, we’ve got a large cutout of Snoop Dogg with a sign taped to him that says “Keep the station clean”. Doesn’t work; the joint is a pigsty, but we apparently like it that way. When I campaign for general manager, I’m doing it on a “chore chart” platform: Staff members will be ASSIGNED a day to clean.
Other than that, we have nothing. I’ve been asking for a map of Pennsylvania, but so far nothing.
Robin
I had one that said something to the effect of (it’s been awhile!):
“If you’re surly, irritating, or just plain rude, pay $10 before beginning to speak”.
As I worked in insurance, it fit. And some clients actually paid it up front.
My campus radio station back in the mists of time had ‘Just Say NO! Or at least LATER! to drugs.’
Two things on the bulletin board:
and
There’s also a New Yorker cartoon in one of those roach-clip picture holders on top of my monitor, with a guy sitting at a desk, talking on the phone, saying “I like things to be done my own particular way by someone other than me.”
“I’m not shy … I’m just examining my prey.”
“Coffee - is the planet shaking or is it just me?”
“Freak” on my monitor (from a co-worker)
The Dispair Change poster and the Motivation desktopper.
Also:
[ul]
[li]Dick and the King magnet (Nixon and Elvis)[/li][li]Moe about to hit Curley with a meat cleaver magnet[/li][li]A Jesus Action Figure (“with posable arms and gliding action!”)[/li][/ul]
I have this stuck on the wall of my cube.
My whiteboard says “Today is Anti-Procrastination Day!”
But “Today” is crossed off, and “Tomorrow” is written below it.
Cool signs and I love Get Fuzzy!
Bucky Cat is on my daily reading list. 
My first sign is for my customers because of the unusual amount of crap they give me over their late fees:
My second sign is for me because of the unusual amount of crap I get from my customers:
Hmmm. Is Ben Fanklin someone I should know about?
Yes, he’s a vey, vey wise man. 
Coffee time!
On the wall people see as they come toward my desk:
"Do not meddle in the affairs of dragons, O Foolish Mortal…
For thou art crunchy and taste good with ketchup."
And of course a sign designating ME as the local dragon.
In my cubicle I have several signs, many of which are Dilbert cartoons, but I also have one that says:
THE FLOGGINGS WILL CONTINUE UNTIL MORALE IMPROVES.
I took it as an ominous sign when the HR manager came down and asked if she could have a copy of it. :eek:
I used to have one that they made me take down because I now work in a customer-visible area. It said something to the effect of OSHA regulations state that I can only have 6 people on my ass at any given time, so until I get handrails installed GET OFF MY ASS.
Heh.
There were things against which we were powerless - Johnny Cash
I’ve got this one up, though it’s mainly obscured by my monitor: Mediocrity
… and also my Word Police Academy certificate.
Some favorites I have seen: