What is the correct octave for the vuvuzela?

The majority of them sound an approximate Bb below Middle C

This question must have been spurred on by the question about vuvuzela concerti, in which case it is certainly in the right category. Just for the sake of testing, I tried starting to ask a question about the vuvuzela, and the first category suggested was Sports > Football (Soccer) > 2010 FIFA World Cup(TM). I don't know if many of the answerers in that category can tell a treble clef from a bass clef.

Anyway, to answer your question, based on my hearing a short clip through computer speakers, I would say that a group of vuvuzelas sound a microtonal cluster centered around B-flat below middle C.

Your confusion is understandable because the most famous vuvuzela concerto by the anonymous composer notates the instrument on a piano grand staff with a sustained B-flat above middle C for the duration. John Matthews, by contrast, correctly notates the instrument in the B-flat below middle C, but I think I would have used the bass clef rather than the tenor clef, which is most likely unknown to the vast majority of vuvuzelists. (The bass clef might be somewhat new to them, too, though).

This is not a classical music question. Nor would questions related to kazoos either.