The Museum of Face Breaking opened in Mizniaport during the Great Monster Uprising approximately a month after the imprisonment of Oldric the Pirate, Beldric the Enchanter, and Tandric the Trapwright. It was dedicated to the life and career of Bozbik the Face Breaker (and to a lesser extent, the other adventurers in his family. They might not have been called Face Breakers, but their exploits and adventures still inspired Bozbik to become the Breaker of Faces that he was). The museum showed trophies and souvenirs from many of Bozbik's adventures (such as weapons of enemies, skulls from powerful monsters, rare treasures he had found but chosen not to sell, etc.), and served as a means of boosting his own (already quite impressive) reputation.  Bozbik was a barbarian adventurer first, but he recognized the money that could be made as a celebrity too, and used things like the Museum of Face Breaking to act as a supplemental source of income.  The place probably also had a gift shop and snack bar.

It is known that Bozbik originally intended to put the Spear of Zoz into the museum, but later handed it off to "Detective Softly", an adventurer who helped him capture Oldric, Beldric and Tandric.

SOURCE(S): Legends of Zork (game, personal correspondence with author of "Enter the Face Breaker' quest)