7 Years ago - The Big Bang Theory: "The Bitcoin Entanglement" episode was watched by 13.84 million people (mostly adults 18–49)

"As Sheldon explains to his friends, bitcoin is an online currency, there’s a limited amount of it, and they can get some for themselves by “mining” it, or writing code to solve complicated math problems.

Add snacks, and that sounds like the makings of a party for this gang, until Sheldon warns them that there could be major tax implications and gets goosebumps when he imagines the time he’ll have to — get to — spend on the phone with the IRS.

Leonard, Raj, and Howard decide to tackle the project without Sheldon."

source: https://www.vulture.com/2017/12/the-big-bang-theory-recap-season-11-episode-9.html

As with most early adopters, they soon got bored and lost the flash drive containing the private key.