We look forward to new exhibitions at the ICA because with each one, there’s an opening party. Tuesday, the museum celebrated the opening of “This Will Have Been: Art, Love & Politics in the 1980s” with a throwback bash featuring an all-’80s DJ set and lots of dancing. Curator Helen Molesworth was cutting a rug, and even ICA director Jill Medvedow, who recently broke her ankle and is wearing an enormous cast on her foot, was out on the dance floor. (She was moving gingerly.) The crowd included artists Charlie Ahearn, Judith Barry, AA Bronson, Mary Heilmann, Lorraine O’Grady, Michael Owen, Lari Pittman, Stephen Prina, and Tim Rollins. The multimedia ’80s exhibition, which includes works by David Hammons, Deborah Bright, Gerhard Richter, Jean-Michel Basquiat, Raymond Pettibon, and Dotty Attie, runs through March 3.