SWEET CHARI-TEE: Donna Karan has a strong social conscience and, for fall, the designer and her DKNY team have cooked up a special scheme. DKNY’s 20th anniversary celebrations continue this season, and at Sunday’s runway show, every guest will receive a T-shirt featuring an illustration of a “DKNY Girl.” The T-shirt’s back will feature information on five different charities: The Fund for Public Schools, City Harvest, The Doe Fund, Cityarts and Donna Karan’s Urban Zen Foundation. Guests can e-mail firstname.lastname@example.org to pick their favorite one, and DKNY will make a donation on their behalf. Those who didn’t make it to the show can buy the $65 T-shirt at DKNY stores, select stores that sell DKNY and dkny.com next fall. The hangtag will list the same charities, and buyers can log on to the brand’s Web site to make their pick.