For Christmas last year my fiance's best friend got us a glass gravity bong. He bought the tube glass piece (that you push down) at a head shop so it has a bowl in cork for the top. then got a big glass vase at a craft store. We used some rubber tubing to make it a perculated gravity. Oh man it is sweet! We usually only load personal bowls because to do it right you need to use it ALL.
mmmmmmm T H I C K cloudy smokey goodness!