The Poohbahs are a secret, silly society on Fraggle Rock.
Among their solemn, time-honored traditions are calling each other "Fritz" and requiring potential new members to recite an oath in the "Uffa-fluff" language. The Beggler-Beg and Vanguard are some of the official Poohbah positions held by secondary characters. There is also a Mind-Reader who sees if a potential member is worthy to join the Poohbahs.
In the Fraggle Rock episode "The Secret Society of Poohbahs," Mokey Fraggle desperately wants to join their organization. As it turns out, all the main characters of Fraggle Rock are part of the society.
At the end of the episode, it is mentioned that the Poohbahs are focusing on getting Boober Fraggle to join.