ESEA League, one of the largest PC gaming leagues, has admitted to putting code into the league's client software to "mine" bitcoins, the open-source Internet currency now exchanging for around $130 per. The league is offering free memberships as some members complain the code damaged their video cards. Eric Thunberg, a league administrator (who goes by the forum handle ipkane) and one of the owners of E-Sports Entertainment Association, told users the inclusion of Bitcoin-mining code began as an April Fools joke that he and ESEA's senior software developer intended to abandon. "We ran the test for a few days on our accounts," he said, "decided it wasn't worth the potential drama, and pulled the plug, or so we thought." Users discovered the Bitcoin mining when they noticed their GPUs carrying unusually high loads over the past two weeks. Bitcoins are an electronic currency whose supply is controlled by a massively complex cryptographic equation. Bitcoin mining is the process of attempting to solve it, and it requires a lot of computing power to do so. Stringing together a network of users, witting or unwitting, is a way to do that, similar to the old Folding@home app on the PlayStation 3, used for genetic research. The idea is that when a computer is sitting idle, it gives its GPU over to the application. About an hour after whistleblowers posted in ESEA's forums, Thunberg admitted the problem, blaming a server restart for "a setting getting changed which enables it for all idle users." At first he said fewer than two Bitcoins were mined by the ESEA clients, worth about $280. Further inspection, Thunberg said, discovered that the code had been running for more than two weeks and that about 29 bitcoins had been mined, worth $3,600. "This is way more shady than I originally thought, and as the person who is ultimately responsible for everything it's 100 percent my fault." Thunberg promised that a client update stripped out "all the btc stuff," and "in a blatant attempt to buy back your love," he offered a free one month membership to all users who held premium memberships in April. He also said all of the money made off the mining would go into a tournament prize pool "so at the very least your melted GPUs contributed to a good cause." One user said his card "maintained 90celcius+ for an extended amount of time," and he's getting video errors. He accuses ESEA of frying his video card. But another, in the same thread, said his "560tl 448core was running 93 C for who knows how long," but that it "seems fine for now." Kotaku reached out to Thunberg through an email address associated with his holdings company to ask if he didn't believe user claims of GPU damage caused by the ESEA client. No response was received as of publication. ESEA League has been in existence for about 10 years, supporting games such as Counter-Strike, Team Fortress 2, and League of Legends. Popular competitive gaming league ESEA admins caught installing Bitcoin miners on player's computers without consent, stole $3,602 dollars [Reddit via NeoGAF]