Congrats to Penatonix! This group won The Sing-Off near the end of November 2011 and soaked in the applause as a result.

You're looking at a photo from R&B night on The Sing-Off. The theme episode featured the show's final five groups.

Nick Lachey keeps The Sing-Off humming along. To very low ratings, but still.

Thumbs up, Nick Lachey! The Sing-Off host makes his way to the stage in this photo.

Do your thing, Vocal Point! This group takes to the stage during the 10/17/11 episode of The Sing-Off.

Pentatonix takes to The Sing-Off stage here. The group is performing on the 10/10/11 episode of the show.

The Deltones are in action here. They are one of many acts hoping to win The Sing-Off.

Afro-Blue takes to the stage in this photo. It's a shot from week two of The Sing-Off competition.

Season three of The Sing-Off is underway! These contestants hope to be left standing at the end.

The Sing-Off is getting a major push by NBC in the fall of 2011. It anchors Monday night programming.