Trapdoor

The trapdoor is a new block type implemented in the beta 1.6 update.

They are intended to be placed over a single-block hole (but can be placed over a block as well) with a solid block directly adjacent. When activated, they will then open by flipping upwards toward the adjacent block. If that block is destroyed, the trapdoor is as well. Just like doors, trapdoors can be activated by redstone. When placed outside, rain and water do not pass through a trapdoor.

Crafting
When crafted with six wooden planks, two trapdoors are created. Video

Uses
-Drawbridge: If you place the trapdoors in a trench in this fashion:

xxxx

xttx

xttx

xxxx

t=tdoor x=block You can create a fairly good drawbrige. You can extend it lengthways, but not widthways. You can also attach redstone to automate it.

Bugs
Trapdoors seem to break faster using a pickaxe instead of an axe, like wooden slabs.

Trivia
Much like the piston is based on a mod developed by Hippoplatimus, the hatch is very likely based on a mod from DJoslin. (http://www.djoslin.info/trapdoor.php) Trapdoors may not be placed next to double half blocks.