The lights are on
To start off with, League of legends is free. You have no excuse not to go and try it immediately.
Now on to the game. The game is largely based off of the Warcraft III mod known as Defense of the Ancients (or DotA). Many of the people who work at Riot Games on League of Legends are former members of the team that created DotA.
The gameplay of League of Legends is entirely PvP based (with the exception of training bots that you can play against offline). Teams of either three or five players compete against each other to destroy the enemy base, or nexus. Players take control of a single champion from a top-down RTS-like view that gains experience and gold from killing enemy champions, minions, or monsters. Experience is important: it allows your champion to level up and drastically improve any of five abilities. Gaining two levels over an opposing champion is a significant advantage. Gold is arguably more important. Getting more gold than your opponents means that you can purchase better equipment in the match. Different gear greatly improves your champion's stats and grants unique effects like magic shielding or slowing attackers.Having the right items can change the entire course of the match and defines the endgame battle when all champions reach the level cap of 18.
There are certain complaints regarding the accessibility regarding the game that i have heard from a few players. These are problems that I never encountered. I have never played DotA, so I entered completely fresh, with no experience. The matchmaking is designed to link up players of a similar skill level. Now there are always some people who have played DotA for a long time who are just joining League of Legends or people who have played LoL for a while that want to be bad sports and prey on newbies. But those instances are few and far between. Most people will offer constructive criticism and be polite. The game also provides a basic tutorial and practice games to hone your skills. I recommend bypassing these entirely and throwing yourself into the flames of the PvP experience. You will learn faster and have more fun.
Outside of the gameplay, there is an outside leveling system based off of experience that you accrue from playing the game. Win or lose, you get experience, though winning grants more. This experience levels up your account and unlocks various minor power-ups that help shape your play style in-game. Playing the game also grants you points that you can use to unlock runes (another way to improve your champions stats) and champions. When you just start out playing you will have access to a small selection of champions that change on a weekly basis. This will allow you to get a feel for the roster of champions, since they all are very distinct and play differently. When you find a champion that fits your style of play, then work towards purchasing said champion. This means that you will be able to play as that champion even if it is not in that week's rotation.
To finish up, League of Legends is a great experience that is worth checking out (because it is free). There might be some issues with accessibility, but not so much the game's fault, but more due to human jerkishness.
Oh, also, this game is free!
Below is the sweet opening cinematic:
Why is it that I haven't played this game yet? It sounds (and looks) like something that I'd enjoy very much. Plus it's free and that's always a good thing. The opening scene sold me on this. I think I literally had to pick my jaw up from the ground when it finished.