From today (March 17, 2011) through March 20, 2011, Gap is having its Give and Get event.
Basically, you need to sign up for emails from Gap and they'll send you a coupon that you can use to save 30% at Gap, Old Navy or Banana Republic. Or click here for a coupon and fill out the requested information.
With each coupon use, the stores will donate money to a charity. The choices include the Juvenile Diabetes Research Foundation, Feeding America, Teach for America, the Leukemia and Lymphoma Society and Habitat for Humanity.