League of Legends is one of the top mmos, The game has a huge amount of active players, staff calculate at aprox 32 million active players. The game just started Season 3 and it's totally free. Atm LoL got like 105 champions or somewhere around, didn't count em. The updates come every month , twice or maybe thrid time. This is a MOBA game, where you fight with your team, maximum 5 players in a team to reach exp for lvling and IP (gold to buy new champions/ rune(that make you little bit stronger)/page runes(where you put ur runes)/masteries(you gain 1 mastery point each lvl, maximum 30 masteries at lvl 30). The game is so fun, that every week there are alot of tournaments where you can join free and win from 10euros to 1000euros and much more, but from 1000euros up only pro players wins.
If you are intersted in this game, and wannna give it a shot, you can join by my refferal here : *snip* and you can read the tutorial here
http://eune.leagueoflegends.com/learn/new_user_guide. Have fun, and if u want help in game, i play on EU NE server ing GoldAng3l