It’s that time of year. A cappella rush is upon us, and several of Yale’s groups are attempting to entice members of the class of 2020 with singing desserts. Mixed Company will sing for you at 8:30 p.m. tonight in the Davenport dining hall. Living Water performs in the Saybrook Underbrook Theater at 10 p.m. and the Spizzwinks(?) will sing in Sudler Hall at 7 p.m.