If you're not on the internet a lot, just to check on here mostly, there are a ton of Dark Ascension previews that went up today!
But for now, instead of doing a rundown of some interesting cards, I'm gonna give you a few hints about what's in the previews:
1) There are only 13 new Double-Faced cards. Yep...13. And not all of them are creature-to-creature or Planeswalker-to-Planeswalker.
2) Reverse Persist, anyone? Yep, it's here. :)
3) The Pre-Release and Release cards are still Double-Faced Cards...and they are creatures. They come from 2 colors not used in the last go-around in Innistrad's Pre-Release and Release promos.
4) A new mill card comes around...and if you Flashback it, it's twice as potent. :)
5) A 1-mana 2/1 that has its own form of Flashback.
6) A card that says "destroy all Humans." No, I'm not putting words into this card's metaphorical mouth. It doesn't say "Choose a creature type, then destroy all creatures of that type." It says "destroy all Humans." :)
Have fun thinking about these! :)