For those of you who have experienced countless deaths in Don't Starve, countless more await with the addition of the Reign of Giants DLC, which debuted on Steam today. After you download the add-on you can basically toggle it on or off on the main menu, granting you access to new items, characters (Wigfrid and Webber), enemies, an extra save slot, and more seasons (spring and summer).
This is technically an Early Access product, but it seems to be essentially finished. The PS4 version of Reign of Giants has been delayed, with more info to come "soon."
Reign of Giants [Steam]