Resilient underground-electronic record store Halcyon opened its fourth incarnation earlier this month, inside of Williamsburg club Output. The hybrid cafe/record shop, which launched in Carroll Gardens in 1999, took over the space previously occupied by Output’s Stilton House room and is now hosting a weekly open decks Record Party on Sundays from noon to 6 p.m. It’s described as “every vinyl diggers dream opportunity to climb behind the decks and show off their proudest finds.”