This and blunts is all i smoke out of on party nights [weekends, no school, special occasions.. etc]
Blunts hold alot of weed and because they are so thick you get big ass hits but they can't hold a candle to the hits you get from gravity bongs.
Also, if you want to experiment with some other drugs besides buddha, this is the perfect way to get a nice big salvia hit to trip your balls off.
What you will need...
1. A Bucket [Example]
2. A 2 Liter Bottle, A 3 Liter Bottle or a Milk Jug (Not all three, just choose, i use 3 liter bottles)
3. Foil (About 3"x3")
4. A Knife (Or maybe a sharp pen?)
5. Rubber Band (Optional)
How to do it...
Step one, Making the Bowl
Whatever kind of bottle you are using, you will need to make the bowl using the cap so this will work with all three example bottles. Start by taking off the cap and poking a pen sized hole in it. When i make my bowls i start by sticking about 1/2 into the hole and poking holes in it to act as a screen, i then build a vocano like foil structure on top of it and hold it on to the cap using a rubber band.
Shitty Diagram: http://supasic.com/images/cap.bmp
Step Two, Making The Chamber
This is where we use the actual bottle itself. Personally i use a 3 liter bottle due to it's size and width.
Giant chambers are useless if they are not wide, a thin chamber will result in weak air suction and therefore lack of the monster rip you desire.
3 Liter sodas are perfect, they are big, wide and will get you fat rips, milk jugs also work very well.
Make the chamber by merely making a straight cut at the very bottom of your bottle. leaving a flat edge to get as big of hits as you can get.
Another Shitty Diagram:http://supasic.com/images/2liter.bmp
Step 3, Getting your fat ass mother fucking rip
Put the 2 liter bottle in your bucket. Fill your bucket up with water so it goes about 1 inch away from the bowl.
IMPORTANT Load your bowls with the cap off or with the bottle already compressed down to the bottom. Remember this when you are blazed. One very high stoner could cause a whole bowl to be shot into your bucket of water by loading the bowl and shooting air from under it with the bottle.
Compress your bottle as far as it can underneath the water without immersing your bowl. load your bowl. Hit it as if you were hitting a pipe by holding the lighter over the bowl and slowly, SLOWLY pulling up on the bottle. This creates suction through the bowl without you sucking on it.
When your bottle is nearly to the top of the water, toss your lighter to your friend, get on your hands and knees, unscrew the bowl and take your rip while compressing the bottle back down at a quick but steady rate.
Using this method will push lots and lots of really dense smoke directly into your lungs and, if done successfully, you will get a very big rip and get very high.