Factions: A community-run game mode. Now featuring: Bandle City, Icathia, Bilgewater, and Freljord
http://i.imgur.com/VXlADZx.png
Factions is run entirely by volunteers. It is not an official Riot project, though we hope to convince Riot that it ought to put something like this into the game mode rotation.
For a couple years now, some of us have been running Factions, a community game mode inspired by Riot's original "Noxus versus Ionia" match. The basic idea: we pick some factions, like Ionia or Demacia, create lore-based Champion rosters for them (sometimes bending the rules a bit to make them more playable), come up with some in-universe lore reason for them to be scrapping on the Fields of Justice, and then play it out. The story develops based on how the matches go. Every few months, we switch in new factions and a fresh dispute.
If you're curious, come sign up for a faction (Champion lists here), join the "Factions" in-game chat:
http://i.imgur.com/1qBKUNl.png
and try it out.
On weekends, we have shoutcasted Featured Matches at 12:30, 1:30, and 2:30 Pacific. They're streamed at twitch.tv/LeagueFactions. But you can also set up a match anytime, through the Factions chat. (If you hang out in the Factions chat, you'll probably get some custom game invites for Factions matches; the standard procedure upon creating a match is to just invite everyone in the chat.) Matches are scored and added to the "Balance of Power", a running scoreboard that abstractly represents how the story is turning based on the matches.
All skill levels are welcome; playing with a range of skill levels is part of the fun. (It can also be a good learning experience.) We've compiled data on how the various rank matchups tend to go, and we use that data to adjust point values. So if you end up on a team of a bunch of Silvers and Golds fighting a bunch of Golds and Plats, the match will be worth fewer points if you lose and more points if you win, to keep things fair.