Ellen celebrates Cinco de Mayo, and you're invited to the party. Check out what happens when Ellen is let loose on historic Olvera Street in Los Angeles and receives a lesson in Mexican culture. Joining Ellen for this celebration is ELLEN POMPEO from the hottest series on TV, "Grey's Anatomy." And, CRAIG FERGUSON ("The Late Late Show with Graig Ferguson") talks about his best selling book, "Between the Bridge and the River."