Brewfest will be running starting today September 20 and ends on October 6.
Quests: All lead-in, ram-racing and daily quests are allowed. Pacifists may not want to do ram-racing since you’re whipping the poor thing… but there will be nothing there to technically disqualify you.
Loot: You can cash in your Brewfest Prize Tokens for white-quality Bavarian brewer gear and the new helm piece.
Coren Direbrew: Since this is in a dungeon, it’s not allowed for any Iron, Blood Thirsty or Pacifist.
Brewfest Enthusiast: At 615am & 615pm, Mekkatorque and Vol’jin issue speeches. Everyone nearby gets a 2-hour buff that grants +10% experience. This buff is not allowed. If you happen to be in the area when the buff is applied, you can simply right-click it off.
For a full run-down of Brewfest you can visit WoWHead’s Guide: http://www.wowhead.com/news=249190/brewfest-2015-guide-september-20th-october-6th