Haven't heard of arguably the most amazing accapella group, Pentatonix yet? 

Vocal sensations and winners of season 3 of NBC’s The Sing-Off, Pentatonix are taking instrument-free music far beyond anyone’s wildest expectations. Named after the world’s most widely recognized five-note musical scale, this vocal quintet has transformed one of pop music’s purest and most soulful expressions into an exciting future, filled with limitless sonic possibility. Pairing their intricate arrangements with cleverly re-imagined pop songs, Pentatonix have quickly cultivated a sound and style that is entirely unique and undeniably infectious.

Check out their cover of Macklemore's "Can't Hold Us"!

Connect with Pentatonix:
Facebook: http://www.facebook.com/Pentatonix
Twitter: http://twitter.com/ptxofficial
Youtube: http://www.youtube.com/user/PTXofficial