The Museum of Modern Art and PS1 curator Klaus Biesenbach are continuing to urge people to volunteer after Sandy. “We realized that this can only be repaired if citizens help other citizens,” he told us after visiting the Rockaways on Saturday. “The damage is too massive to just be repaired the usual way. It needs the help of all of us New Yorkers. It is getting very cold.” In addition to organizing volunteers for next weekend and opening the doors of PS1 for shelter, Biesenbach has written an open letter to Mayor Bloomberg and all New Yorkers encouraging them to help out in the recovery effort. It is signed by Marina Abramovic, Lady Gaga, Adrien Brody, Madonna and a number of other artists.