The cooperative card game Hanabi may be billed as a memory and logic puzzle, but repeat players discover the metagame of devising and fine-tuning an additional "language" of information-laden conventions. We invite veteran Hanabi masterminds and curious newbies alike to come learn, share, and play. This informal session will be tailored to attendees' interests and led by a software engineer and a learning scientist who have played Hanabi almost daily for four years.