We've said it before, absolutely nothing helps out a PSA like liberal drug use by the creators. Here then is One Got Fat: Bicycle Safety, a PSA from 1963, possibly the strangest bit of film we've seen, period.
"A group of children, all wearing ape masks, rides their bicycles to the park for a picnic. Along the way, all but one are eliminated for violating basic bike safety rules. Think about that description, baring in mind that the goal here is to help children. Not one thing fits.

One Got Fat: Bicycle Safety [Internet Archive]