What are your interests? Any particular saturday? If you're interested in music try the blind pig perhaps. The Ark has various shows with a lot of folk. Mash is a nice bar below the Blue Tractor but will likely be packed during the academic year, as it's grown in popularity. 8-ball and circus are decent to shoot some pool. More local-college mix as opposed to south u bars. Ann Arbor Brewing Company (ABC) has good beer, darts and shuffleboard. There's kayaking available on the Huron. Hiking around Birds Hills, Eberwhite woods or the Arb are an option. Museum of Natural History and the UM Museum of Art (UMMA on State street) are both right on campus with maybe a 5 min walk apart. If you have kids there's a hands on museum near downtown. If you like sushi Nagomi just opened up on liberty. Place is amazing. Early evening in spring or summer hit up Bills Beer Garden.