The  Hearthstone Invitation Letter begins  It’s Hearthstone’s Anniversary! which directs you to talk to MC Farala, the Hearthstone Master of Ceremonies in Valdrakken. A free starter deck will have you on your way to  Play Hearthstone! and collect cards.

• Take a seat at a game table in Valdrakken, Stormwind, or Orgrimmar to play with an opponant
• Play  Hearthstone Wild Cards near, not at, the game tables
• Shady Dealers will sell you a pack of 5  Hearthstone Wild Cards for 20
• Periodically, special encounters will allow you to defeat iconic minions and add them to your deck
• Collect cards for achievements and rewards, including your own  Hearthstone Game Table

Sit at a Hearthstone table and play cards against an opponent. Wild Cards can be played by nearby players to spawn a random rarity minion on either side of the field. There is no reward for winning.

At the top of the hour a special event portal will spawn. This spawns Whizbang who will attack with several iconic Hearthstone minions to defeat. Rewards include a random card for your collection and may include special prizes like transmog items and the  Collector’s Carryall, or even a mount, toy, or pet.

The following can be looted from the Special Event:

• Mount:  Compass Rose
• Pet:  Sarge
• Bag:  Collector’s Carryall
• Hearthstone:  Stone of the Hearth
• Tabard:  The Tavern’s Tabard
• Cosmetic Belt:  Taverner’s Belt
• Cosmetic Hat:  Reno’s Lucky Hat
•  Hearthstone Wild Card
• Random Collectable Hearthstone Card