Some of the old PSAs of yesteryear are fantastically funny in retrospect. Like this one, that talks about how if you leave the radioactive, blasted wasteland after a nuclear attack, you're a treasonous communist, and a coward:
Here's one for all of you who didn't know better. Remember, if you're on your period, for god's sake, square dance only in moderation!
You can see a great bunch of these old PSAs at The 6 Most Unintentionally Hilarious Old School PSAs.