Halloween Update

Announcement
The Minecraft Halloween Update is planned by notch to be released on October 31, 2010. The planned features to be released are:


 * A "Hell" world that can be used for quick travel, where you "portal in" walk ten meters and then "portal out" and you're hundreds of meters away
 * New monsters
 * More danger at deeper depths in-game
 * Torches that eventually burn out, but are re-lightable, and the introduction of lanterns as a new infinite light source
 * Fishing
 * Multiplayer fixes
 * Craftable Jack-O-Lanterns and pumpkin helmets
 * Craftable watch
 * And more. [See image]

This was announced on October 4th, 2010, and can be seen at minecraft.net/boo

On October 8th, 2010 a new type of block was announced. And on October 11th Notch wrote the following on his twitter: "I just made the most unfair mob ever even more unfair. You will hate the Ghast."

Media
No gameplay footage has been released yet, but there are some announcement videos and commentaries  here and  here.

On 10/10/10 Notch revealed the following screenshot on his blog: