Ever played league? I've played that game for over 4 years now, pretty much the most dedicated I've been to a game.
I have never heard of it! Is it a computer game, board game...??
It's a computer game made by Riot Games.
How do you play?
Well you basically choose a champion, which is a character with a set of abilities to use. It is 5 champions vs. 5 champions and you win by destroying their nexus.
Is it  interactive with other players online?
Yeah! It's what's called a MOBA, meaning a massive online battle arena.
Oh wow so you can play with many different players at once?
Oh yeah, I've met many of my best friends playing it and playing with them. It was and still is the most popular online game in the world.