Penny Marshall/Rob Morrow/Ellie Lawson/John Moceo

PENNY MARSHALL sings! Watch her rerecord our theme song! The star of the new TV show, Numb3rs,"" ROB MORROW is here. Ellen's favorite new singer, ELLIE LAWSON performs. And, you won't believe the performance of 12-year-old JOHN MOCEO as he rocks ""Green Day"" on his accordion!