Ever done that thing where you put a £10 note in your winter coat pocket, forget about it until a year later and feel like you've won a prize?
Well that's nothing compared to the elation Christopher Koch from Norway must have felt recently.
Back in 2009 Koch became intrigued with a new form of internet currency, the Bitcoin, while working on a thesis on encryption.
Out of curiosity he decided to purchase some and spent 150 kroner ($26.60/£16.33) on 5,000 of them.
And then he forget about it.
Fast forward to April of last year and the increasing popularity and media coverage of Bitcoins prompted him to check on his purchase.
All $886,000 (£552,370) of it.
Koch was able to buy a plush apartment after exchanging only a fifth of his haul.
The rise of Bitcoin has been meteoric - if not slightly turbulent.
The scourge of centralised central banking dropped in value by $160 (£104) in one day in April 2014 after a sudden panic sell-off - but it was worth 6.5 times what it was two months ago.
Bitcoin's value spiked at $266 (£173) before falling to $105 (£68). It recovered slightly after its hefty fall to end the day on $130 (£84).
Last year its value was stagnating at $5 (£3.24).
It is becoming increasingly recognised as a legitimate form of currency. Canada recently opened Bitcoin ATMNS and German recognised it as a "unit of account" in August.