Such an amazing cover of "Cups ("When I'm Gone" by Pitch Perfect) by Sam Tsui, Alex G, Kina Grannis, and Kurt Schneider!
Check out other covers by these guys, they won't disappoint!
http://www.youtube.com/thesamtsui
http://www.youtube.com/kurthugoschneider
http://www.youtube.com/kinagrannis
http://www.youtube.com/AlexGMusic7