I was quite delighted to learn about James Randi who, having had an illustrious career as a stage magician, was a prime example of mythbuster. Alas, I only discovered him when he was in the news for the wrong reason, his death.
New York Times has a great feature on Randi. Most famously, he has faced perpetuators of paranormal activity head on, debunked many pseudoscientific beliefs many a time. Although, from the article it seems like he might not appreciate me calling him a mythbuster.
I’m an investigator. I only expect to show that something is not likely.
Alongside another beloved mythbuster, Carl Sagan, he started the Committee for Skeptical Inquiry. While I haven't watched it yet, An Honest Liar is purported to be an excellent documentary on his life's work.
Magicians are the most honest people in the world: They tell you they’re going to fool you, and then they do it.
In one interesting effort to dispel the myth of psychics, Randi wanted to pull off the greatest stunt ever - every night before sleeping, he used to write cards labelled to the effect "I will die tonight", and always dispose off all the old cards for the days he didn't. If anyone naive were to discover the card in the event of his death, they would believe he truly foresaw death. Alas, he gave up on this experiment because "he didn't get lucky enough".
Showing such resolve, he was quite an extraordinary individual and for sure positively contributed to society.
I also previously wrote about Inoue Enryō who did some popular mythbusting in Japan. I believe the role of mythbusters has become increasingly important in the age of fast information. I wonder who is carrying the baton forward.