Garrett M. Graff has this article for Wired about the Mirai botnet denial-of-service attack, saying that it was powered by angry Minecraft server operators and players:
As the 2016 US presidential election drew near, fears began to mount that the so-called Mirai botnet might be the work of a nation-state practicing for an attack that would cripple the country as voters went to the polls. The truth, as made clear in that Alaskan courtroom Friday—and unsealed by the Justice Department on Wednesday—was even stranger: The brains behind Mirai were a 21-year-old Rutgers college student from suburban New Jersey and his two college-age friends from outside Pittsburgh and New Orleans. All three—Paras Jha, Josiah White, and Dalton Norman, respectively—admitted their role in creating and launching Mirai into the world.
Originally, prosecutors say, the defendants hadn’t intended to bring down the internet—they had been trying to gain an advantage in the computer game Minecraft.
VDOS was an advanced botnet: a network of malware-infected, zombie devices that its masters could commandeer to execute DDoS attacks at will. And the teens were using it to run a lucrative version of a then-common scheme in the online gaming world—a so-called booter service, geared toward helping individual gamers attack an opponent while fighting head-to-head, knocking them offline to defeat them. Its tens of thousands of customers could pay small amounts, like $5 to $50, to rent small-scale denial-of-service attacks via an easy-to-use web interface.
A similar service was used to attack the ioquake3 master server in the past. It was surprisingly easy for it to be launched on an ongoing basis.