This is a video from June 19, 2011 as someone watches BTC go from 18 dollars to .01 and then back up due to a glitch on Mt Gox. It is kinda long, but, it is interesting.
According to some comments on Reddit (I didn't do any research myself into this) this was due to some hacking at Mt Gox.
Anth0n: This crash was caused by a malicious actor due to a Mt. Gox vulnerability where they were able to sell BTC that was not theirs. The transactions were reverted by Mt. Gox shortly afterwards.
Chuck_Portis: That's part of the story. The reason they sold the Bitcoins so cheap was because the account they had compromised had a $1000/day withdrawal limit, based on the prevailing price on the exchange at the time. So the hacker crashed the price down to 1 cent, which allowed them to withdraw thousands of BTC. If they had just tried to withdraw at the regular price, they would have been limited to about 80 BTC before hitting their withdrawal limit.
Also, I am not sure which is crazier, that this guy watched all this happen and he didn't buy or didn't sell throughout this video.
