Nailed by Variety as “A vivid portrait of a lost libertine paradise,” Gay Sex in the ’70s: A steamy romp, released last year, is now on DVD (buy one at Documentarian Joseph Lovett melds gritty black-and-white montages of gay men partying their way through ’70s Manhattan with hazy and nostalgic commentary from the men, including ACT UP founder Larry Kramer, looking back at sex pre-AIDS and its aftermath. A disco inferno indeed.