Sometimes you need to step away from the PC and get some fresh air, which is hard because then you can't play video games. Riot Games is aware of this conundrum and has worked to make it a bit easier, with the release of a special League of Legends smartphone application called League Friends.
You can't play League of Legends with it, but there are a bunch of other useful features for people who take the game seriously. You're able to chat with people in your LoL friend list, and you can receive push notifications when someone has invited you to join a game. That's a pretty small offering, but Riot plans to expand its functionality as time goes on, presumably (or hopefully) with all manner of esports related stats.
The app is now available in North America and Oceania, with other regions to follow shortly after. You'll need either iOS 8.3 or Android 4.1.1 (or newer iterations of these) to run it.