From the last time this came up:

Clarinet: Two tunings, three if you want to get REALLY technical. You need an open G to tune at the barrel, and an in-staff C or B natural to tune the center. I've heard of some clarinetists that tune a high-G in the center joint and tune a B natural to actually tune the bell, but that's not a common thing at all. It matters more with larger clarinets - alto, bass, contra, etc.