Hard to believe in this age of constant nostalgia that there's anything left to know about Lucille Ball, Johnny Carson, or Conan O'Brien, but this video from Mental Floss proves there is -- possibly -- stuff left to glean from comedy history. Narrator John Green covers sitcoms, standup, and movie comedies in this rundown of trivial (but nonetheless interesting) facts about funny people. The "Roseanne" fact is downright bewildering.