You know the underdog-comes-from-behind ending before you even take the disc out of the box, but Harvard Beats Yale 29-29 is somehow stuffed with surprises. Kevin Rafferty’s 2008 documentary about an unbelievable matchup between the undefeated Ivy League archrivals in 1968, which was recently released on DVD, is told simply through mixing talking-head interviews of many of the players involved (including a cerebral Tommy Lee Jones, who played offensive tackle for Harvard) with clips of the televised game. It blends the memories and misrememberings of not just a game but the culture itself: from the buttoned-down bubble of Yale to the politically charged atmosphere of Harvard, where a recent Vietnam vet who had spent months stuck in Khe Sanh was lining up with fervent members of the antiwar SDS. Anecdotes oddly surface about Al Gore, Meryl Streep, and George W. Bush, and the Yale team remembers how much it loved and hated that its undefeated-since-seventh-grade quarterback, Brian Dowling, was the inspiration for the character of B.D. in Garry Trudeau’s “Doonesbury.” While tear gas and picket lines and sex and “whatever turns you on” all enter into the picture, Rafferty, who gained fame with the 1982 anti-nuclear documentary “Atomic Café” and for helping out Michael Moore early on, focuses mostly on the game itself, one of the best in college football history. With 42 seconds left, Harvard somehow finds a way to score 16 points to tie the huge Yale favorites. If it weren’t true, the ending would feel ridiculous. Instead, it is what sports fans yearn for endlessly: the exhilaration of something seemingly impossible happening before their very eyes.