Home Events Deep Talks: Dark Matter Day Trivia Ex... Deep Talks: Dark Matter Day Trivia Extravaganza October 27, 2022 5:00PM 160 W. Main St. SD 57754 Celebrate Dark Matter Day with SURF's trivia night on Thursday, October 27, from 5 to 7 p.m. MT at the Sanford Lab Homestake Visitor Center and online!