I've already written about my favorite silent film comedian, the always amazing Charlie Chaplin. But there is another actor who has similar chops. You've probabaly heard of the guy to the left. He's considered one of the most athletic silent film comedians. While Chaplin may have wooed the world with his Tramp, Buster Keaton wowed the world with the physicality of his comedic stunts. He truly was a great.
While he has many hilarious films (including one called College where he plays a hapless geek who can't quite by the athlete he wants to be to win the girl), there is one that stands above the rest for his subtle humor and beautiful vision.
For a wonderful review of the movie (since I haven't seen it in a few years), please see what Slate magazine's Gary Giddins has to say on The General, a spoof of a real historical event that occurred during the Civil War. The link also includes some sample clips of the movie, which has been rereleased in crystal clear quality (generally the only downside of silent comedies is that they are poor quality since they were made in the 1920s).