Blizzard announced the new Hearthstone expansion, which will be Journey to Un'Goro. Apparently they'll be breaking the pattern a bit and having two expansions in a row (unless my card count is off and there are way more that come with an adventure than I thought.)
Un'goro Crater will have a couple major themes. One is that Elementals will now be a creature type, which will apply retroactively to other elementals.
There will also be plenty of dinosaur creatures, and many of these will have the "Adapt" keyword. Adapt gives your minion three options for an upgrade that will include gaining things like Taunt or Windfury or getting boosts to its stats. The three adaptations you get to choose from will be random, so these will be highly variable minions.
Finally, there will be a new card type called quests. These will always cost 1 mana and will create an effect (tracked similarly to secrets) that requires you to do things over the course of a game to potentially get a very powerful effect. For instance, there is one priest quests that requires you to summon seven deathrattle minions. If you succeed, you get an 8/8 minion that has a battlecry that sets your health to 40.
It seems like Mean Streets of Gadgetzan just came out, so it's pretty impressive to see this announcement so soon.