BiFest is a one-day event celebrating bisexuality, for bisexuals and bi-friendly people. Originating in London, it has now spread to several other UK locations.
Birmingham BiFest will happen on 12 November 2016 at Birmingham LGBT; see this Eventbrite page for tickets.
London BiFest is back, with a new venue at Kingston Quaker Centre. The site at london.bifest.org has details.
Wales has hosted a BiFest every year since 2010. It is likely that there will be one in May 2017 - watch the Bi Cymru page for updates.
Not a BiFest, but a similar event one-day event in Grasgow hosted by The Equality Network. Details on Facebook here.