waterfall or bucket

they all require a 2L bottle. for all of them, make a bowl in the cap.

Waterfall: drill a hole in the bottom, fill with water, cover hole, light weed in cap and release the hole. as the water escapes, the bottle should fill with smoke, enjoy

Bucket: cut te bottle near the bottom so its open ended. put it in a bucket of water, light the weed and pull the bottle up slowly. once it reaces the top, remove the cap and suck on it as you push the bottle to the bottom of the bucket.