For as long as there have been actors, there have been actors flubbing lines. You know there was some dude rehearsing a Greek tragedy way back in ancient Athens who totally screwed up and said whatever the ancient-Greek version of "sh*t balls!" was, and everybody laughed. But according to these things called "scientists" and "historians," there's no footage of ancient Greek bloopers. There is, however, footage from erudite actors from the golden age of film messing up, as YouTube user Via Margutta 51 has compiled for your pleasure:
The "laugh" section around 6:45 will be especially enjoyable for anyone who enjoyed Jimmy Fallon's work on SNL.