A Calabash Pipe is traditionally a smoking pipe made from the gourd of a Calabash.  An example of a calabash gourd is that green looking thing hanging from the tree to the right.  The cooked version of the gourd is the picture located in the upper right hand corner.  Today any smoking pipe which has a long stem that curls upwards into a bowl is known as a Calabash Pipe.  The name now more closely identifies the curves of the pipe than the actually material used in its construction.
A Calabash Pipe is a pipe made for smoking with a curved stem and a large bowl created from a Calabash Gourd (CG).  Your next question, if you’re normal, should be: what the heck is a Calabash Gourd?  I’m glad you asked, because like I said that means you’re normal.  Just kidding for those of you who actually did know the answer.  For the other 99.9% then, a CG comes from a vine knows as a Calabash.  If the vine is harvested early it can be consumed as a vegetable (Image i) and if it is harvested late it becomes hard and can be used as a smoking pipe, bottle or utensil.  The rounder Calabash species are known as Calabash Gourds or bottle gourds because they make bottles out of them (Image ii).  Actually, the Calabash Gourd is one of the first vegetables ever harvested, for a purpose other than food.  I guess that way back in the day they just forgot the Calabash on the vine and when the realized it was inedible they decided to use it as a container.  Common sense, rights.

So that explains what a Calabash Pipe is made from and how it gets its name.  The Calabash Pipe is one of the most famous pipes because it was commonly used by Sherlock Holmes during on stage performances.  The Calabash Pipe won this role because of its size and visibility for the audience during a stage performance.  Most recently the Calabash Pipe won a Best Supporting Actor role alongside Christoph Waltz for his portrayal of a Nazi Colonel in the movie “Inglorious Basterds” starring Brad Pitt and directed by Quentin Tarintino.  The Calabash Pipe was once again enlisted as a result of its stature as Christoph Waltz’s character used it as a means to say without words “My pipe is bigger than yours”.