Itzhak Perlman and Yo-Yo Ma —
Cold temperatures forced Cellist Yo-Yo Ma and violinist Itzhak Perlman to mime along to a prerecording during President Barack Obama's first inauguration four years ago. "I really wanted to do something that was absolutely physically and emotionally and, timing-wise, genuine," Ma told The New York Times in 2009. "We also knew we couldn't have any technical or instrumental malfunction on that occasion. A broken string was not an option. It was wicked cold."