David Letterman - Anna Kendrick's Song and Cup Trick

This video has actress, Anna Kendrick, performing Cups, not just cups the game but sings a song while doing it, on David Letterman. She does this in the movie Pitch Perfect. Now, I'm not asking you to watch the movie but I did want to give Anna kudos and show you this video. If the video isn't showing go here: http://youtu.be/o_9i9Q7KIrU