Nutcracker medley, Straight No Chaser (a famous a capella group) and Joshua Bell (a famous classical violinist)
The playing on this is insane.
There was a famous experiment done involving Bell in 2007, covered by the Washington Post. I described it in a comment a few years ago:
In 2007, this world-famous violinist went into a Virginia suburban Metro station wearing a Washington Nationals baseball cap, opened his violin case, pulled out his $3.5 million Stradivarius, and played a 45 minute concert incognito, which is all on video on YouTube. One woman recognized him and tipped him $20. For those who didn't recognize him, in those 45 minutes he made 32 bucks and change.
Now, listen to this recording and imagine that.