Riot Games is always good about keeping League of Legends up to date, adding new modes and characters, as well as balancing items and current combatants. Today is no different with a rather significant patch to the game. It's nothing as big as the Dominion patch, but balancing is done, a new character is added, four limited-edition Halloween skins are introduced, and Dominion has been altered.
The biggest addition is the western-style, double-barrel shotgun-toting bounty hunter Graves. He's a ranged fighter whose skills emphasize getting up close for short periods of time. I've seen him around in a few matches throughout the day, and he seems like he's a very fun champ to use. The shotgun is fitting for him.
In Dominion, there are a number of changes to how personal score is tallied, to help show proper rewarding for defensive actions. In addition, the global buff is being tweaked to emphasize the early game fighting in that mode. The item Hextech Gunblade is also getting some stat reductions to prevent people from becoming overpowered by stacking multiples of them.
Topping it all off are character balances. Notable changes include Skarner and Corki. Corki's Gatling Gun move is getting some base damage to make it less hit or miss. Skarner is getting attack speed buffs, as well as buffs to the duration of his ultimate move. You can read the in-depth patch notes on the League of Legends website.