Wikipedia
PolyDay is a one-day festival/convention held in the UK, celebrating polyamory. There has been a Polyday every year from 2006 onwards, usually with workshops and discussions during the day and social events in the evening. As of 2012 it became associated with the international event, Poly Party Weekend.
The content of each Polyday's differs slightly each year. Features that have been consistent so far include a basic introduction to polyamory, useful literature, people to chat to, arts/crafts and cake. Other sessions such as activism, fun and games and flirting tend to pop up fairly regularly.
Everyone is welcome, whether they are poly or not, partners, friends or allies of poly people provided they are open and accepting of other attendees. Strict rules apply to photography and members of the press who wish to attend, so as to protect the privacy of other attendees.