One of the less-enjoyable aspects of college life is doing laundry all by yourself. Dorm rooms and sorority houses usually have laundry facilities in the basement, if at all, which can be dark places. Spice up laundry time and use it to get to know one another. Make virgin (alcohol-free) cocktails and start up a game of bingo while clothes are in their spin cycle. You can also ask local laundromats to let you use their machines after hours. Invite a fraternity and make it a mixer.
Social mixers with a lot of people can intimidate shy sorority members. If you want to promote getting to know each other, hold a rotation of five minute one-on-one interviews and make sure that every member meets one another personally. Give prompts for talking, like printing out questions each person has to ask or answer.
Finals and mid-terms are a stressful time, especially for freshmen. Have your cook or kitchen staff make study break snacks, like a fruit plate, cheese and crackers or even hors d'oeurves. Have the snacks set out at predetermined times and have the girls take study breaks together and commiserate about their classes. Another idea is to designate study buddies for a quarter or semester.
Not every girl is a fan of camping, tone it down and have a backyard camp out. Set up tents and tell ghost stories together or play classic camping games like "Truth or Dare" or "I Never." The girls sharing the tents are sure to come out the next morning bonded from late night talking after the lights go out.