“There have been some mighty big deals at this year’s Sundance Film Festival, but there may be no entry there this year that seems more of a slam-dunk for a major breakout than Brittany Runs a Marathon. This terrifically engaging debut feature by playwright Paul Downs Colaizzo is the best kind of “crowdpleaser”: one that earns every emotional beat that might seem formulaic in four out of five similar enterprises. Drawn from the actual experiences of the writer-director’s best friend, also named Brittany, the inspirational story of an overweight New York woman’s long hard road to improvement — not just figure- or health-wise, but also in how she views herself and other people — is sure to become a favorite for those facing similar issues, or indeed anyone who needs a dose of motivational encouragement. It’s also a whip-smart comedy with some real emotional depth ”—Dennis Harvey, Variety. Hilarious, outgoing and always up for a good time, New Yorker Brittany Forgler is everybody’s best friend ― except maybe her own. At 27, her hard-partying ways, chronic underemployment and toxic relationships are catching up with her, but when she stops by a new doctor’s office to try to score some Adderall, she gets slapped with a prescription she never wanted: Get healthy. Too broke for a gym and too proud to ask for help, Brit is at a loss, until her seemingly together neighbor Catherine pushes her to lace up her Converse sneakers and run one sweaty block. The next day, she runs two. And soon, after finishing her first mile, she sets an almost unthinkable goal: running in the New York City Marathon. R. 103 Min.