Above a urinal:

What are you looking up here for, the joke is in your hands.

It's close enough to 4:20

Here I sit where most guys stand
Because I'm using both my hands

FAX

Here you sit, a long line's waitin'
There's no time for masturbatin'

FAX

I can appreciate when sophistication is exposed in a topic such as this....not to post hooor but there were some fine contributions to this topic in
http://www.chiefsplanet.com/BB/showthread.php?t=111071

Set that one on a tee and got away with it...

one sign i saw once----stand close. it's shorter than you think

Please don't throw tooth picks in the urinal --
the crabs have learned to pole vault.

At my high school there was a sign above the toilets that read "Flush twice. It's a long way to the kitchen."

Canadian fishing cabin outhouse

38" Walleye, caught, ate and released