Minecraft Mob Trap

What you need:

1 or more Buckets of Lava
1 or more Buckets of Water
Plenty of Dirt/rock/etc (not sand)
A shovel and pickaxe to make your life easier

Basically, this is a trap to lure mobs in, kill them, and in the process it also drops the items straight into your lair

You start by digging a hole in the ground X wide and 4+ deep. The wider the trap, the more chances of catching mobs you have. On one side of the hole, make a stair way like thing that ends at the bottom of the hole on the other side. at the far wall, dig straight down at least 4 blocks, then hollow out a small room. Connect this room to your base somehow. Now go back up to your hole.

Right above the part that goes down, you need to place a block. Leave one block of space for the water to flow under. Place your lava on this block. Up at the top of the hole, place your water. The water will flow into the hole. Mobs will be swept away and forced against the block. They will try to jump out, and subsequently touch the lava. They will eventually die, drop their items. The items will fall down the hole into your cavern where you can pick them up safely.

This doesn't work with spiders, but they do get trapped underneath the block you placed in the middle.

It's a bit hard to understand. Think you can take some screen shots or record a video? If you want to record a video I suggest using Fraps.

Fyi, this doesn't work in multi-player. At least when I tried it.

You may need a map editor to get the lava to stay in place. Or use a cactus.

The lava and everything works fine, but it doesn't do damage to the mobs, and I already have a cactus one built, but it is by a mob spawner.