This is a permanent pig pit in my yard... although, this year, I have actually re-bricked in the entire pit as opposed to the bricks just being thrown haphazardly as they are in these pics.  The concept is still exactly the same even though the pit looks infinitely more presentable then it does in these pics.

Dig a hole, line it with brick, and then toss a bunch of rocks in the bottom.  You then get a bonfire going for a few hours to get the pit and rocks white hot.  I wrap the pig in clean burlap, some BBQ  sauce and then wrap it in a layer of lettuce and cabbage and then an outter layer of chicken wire to keep it all together and to give me something to grab it with.

The pit then gets a large bag of whole lump charcoal and some hickory chips.  The pig gets lowered in, the lid goes on, the lid gets buried a little bit to keep it insulated and the pig roasts for about 27-28 hours.

I put in some  "air vents" to allow me to control airflow into the pit and then temperature.  The lump charcoal, if allowed to get just a little air, will burn and stay really hot for the full cooking time no problem.

We then take the pig out of the ground, unwrap it and it falls apart.  It is  a tremendous cooking method.   This year's cookout will also feature about 20 kegs of homebrewed beers in 18-19 different styles.