I learned a thing today!

The Romans would put signposts and notices at the intersections of three roads, and that's where we get the word for trivia -- it literally means "three roads" (tri and via).

Because the notices didn't pertain to everyone and thus were neat to know yet not terribly useful, the word gained the definition that it has today -- pieces of information of little importance.

And that was trivia about trivia!

Link for those who doubt me:  http://www.etymonline.com/index.php?term=trivia

(Hat tip to Jeff W. for the trivia)