Best use for a waterbottle, though, is a waterfall. You get so high off less weed.
1. Get a waterbottle and make a hole in the bottom, a bit smaller than a dime, maybe.
2. Make a bowl over the opening, using tinfoil.
3. Poke small holes in the tinfoil using a toothpick or something.
4. Take off the bowl, put your finger over the bottom hole and fill up bottle (not quite to the top) with water or whatever you got.
5. Put the bowl back on put the weed in it.
6. Light the weed, and as you are lighting it, remove your finger from the bottom hole.
The draining water will suck the smoke into the bottle to take the place of the draining water.
7. When the water is all gone, put your finger back over the hole.
Pass the bottle around (or hog it all to yourself 

) and breathe that shit in.