An organization to promote the study of the kazoo in all fields, 

including--but not limited to-- 

performance, construction, history, design, science, composing, education, etc. 

Kazoologist--one who studies the kazoo in one or more of its fascinating fields.

What is a kazoo?

The properties of a kazoo that I consider most important are:

1)  It has one or more vibrating surfaces which amplifies and distorts the sound of the player's voice.

2)  The pitch is controlled by the pitch of the player's voice rather than the length of the air column being altered by slides, fingering, etc.

Kazoos are generally considered to be membranophones, with a separate membrane attached to the body.

Conditions 1 and 2 also apply to instruments that might not be considered membranophones, in that instead of a separate membrane,  the vibrating surface(s) consist of part or whole of the entire body of the device, being one of the following: 

These can be further devided by types of body

A. rigid (or semi rigid) walls of the device vibrate such as Patents 194119, 2587445,

B.  The vibrating surface is flexible and held in shape by

So, are these also to be considered kazoos?

Checking on the US patents that specifically refer to their invention as a "kazoo"
I find that they all can be considered to have tubular bodies and a separate membrane attached to the body (either internally or externally).

So what are the other instruments?  I recommend the term kazoid.

Kazoo with the addition of the suffix -oid 

1. Of similar form to, but not the same as. Having the likeness of. Suffix appended to various words to make an adjective form.

   human → humanoid

   sterol → steroid

   planet → planetoid