The Sing-Off Season 3 Episode 4 (Radio Hits & 60s Classics: Part 2)

Watch The Sing-Off Season 3 Episode 4 (Radio Hits & 60s Classics: Part 2) online here: <br /><br />http://tinyurl.com/6y4tylp<br /><br />Six groups perform current hit songs and classic 1960s tunes.