If you're a Bitcoin owner, today is certainly not a good day. The value of Bitcoins has declined extremely rapidly, dropping $100 in value in just a few hours. Earlier this week, Bitcoin prices were as high as $260. As of the time of writing, Bitcoins were at $149 after having dropped as low as $105.
Some believe the cause of this crash was an inevitable "downward correction" due to the price rising too quickly. Others have suggested that the Bitcoin exchange, Mt. Gox, is suffering from a DDoS, resulting in significant lag time and a destabilization of the market. It'll be interesting to see if the price rebounds quickly or if it takes a slow, but steady, increase.