Roses are red, violets are blue, please touch me there, my balls are so...

We've all seen the large, multi-colored, magnetic letters on refrigerators, right? I assume they're for kids but I personally have never seen a child use them. I have, though, seen drunken college kids and wannabe poets use the little typewriter fashioned ones to spell out perverse and thought-limited limericks (the rhyme schemes are usually intact though, almost like a porn star version of Doctor Seuss). So, are they a seldom used educational toy or just an oddly familiar studio prop used by motion pictures to simulate an intelligent atmosphere for a child? Wish I knew.