For the fourth consecutive year, the Animal Rescue Fund of the Hamptons is turning its thrift shop in Sagaponack into a designer showhouse for the Memorial Day weekend. Six rooms will be styled by well-known interior designers from New York City and the East End for the event, which will launch with a preview cocktail party Saturday at 5 p.m. The shop will be open on Sunday and Monday from 10 a.m. until 4 p.m.