Party like it's 1998! Julia Roberts made what E! is calling a "rare public appearance" yesterday, appearing onstage at the Stand Up for a Cure concert at Madison Square Garden. "Hello New York City!" she said to the audience. "I cannot tell you how excited I am to be in the greatest city in the world to introduce one of the greatest bands of the world." Then, strangely, Dave Matthews Band came out. [E!]