After discovering bitcoins while researching a thesis on cryptography, Kristoffer Koch invested 150 kroner ($26.60) in 5,000 bitcoins in 2009.
He instantly forgot about them until April 2013, when he was reminded by massive media coverage of the anonymous, decentralized, peer-to-peer digital currency.
Bitcoins are kept in encrypted wallets protected by a private key, which Koch had overlooked. Koch was pleasantly surprised when he figured out what the password was: "It indicated I had 5,000 bitcoins in there."
It turns out that Koch's frivolous technology spending, against his girlfriend's wishes, actually turned out to be a great investment.