Although it might not be something that every player ever spends much time with, Ranked play is League of Legends' core game, where he people who really want to test their abilities go to find out how they stack up against the rest of the world. Or at least, how well their team at the time stacks up, trolling, toxicity and all.
With that in mind, if Riot ever disables ranked play you know there is a big reason for it. In this instance, it's because a bug has been discovered with the game's recall function, which normally takes a few seconds to activate before sending players back to their home base. However someone figured out that Riven (and eventually all other champions) could recall instantaneously at any time.
As might be imagined, that creates all sorts of problems for competitive play, so Riot has pulled ranked matchmaking for now while it figures out what went wrong.
"We’re currently working to fix a bug with the Recall spell," Riot wrote in a post on its live status page for the North American League servers at 9:08 PM tonight. "Unfortunately, this particular issue can’t be mitigated by disabling a specific champion or item so we’ve temporarily disabled Ranked while we develop a solution. We will update you all with our progress in 12 hours."
