The second of eight groups compete. The groups include Messiah's Men, North Shore, Pentatonix, Sonos, Soul'd Out, The Collective, University of Delaware Deltones, and Dartmouth Aires.

The six remaining groups from the first bracket of performances sing for the judges' votes.

The six remaining groups from the second bracket of performances sing for the judges' votes.

The top ten groups perform "guilty pleasures" for the judges' votes.

Hip-Hop takes over "The Sing-Off" as the eight remaining groups perform for the judges' votes with an elimination sing-off.

A spook-tacular episode of The Sing-Off this Halloween.

The remaining challengers must get "a little bit country & a little bit Rock & Roll" performing one song from each genre.

The top five groups refine their swagger with a night of R&B hits.

The top four groups take on the challenge of mashing up two hit songs -- America votes for the champion.

The winner is revealed -- live season finale!

"The Sing-Off Holiday Special" will be filled with holiday and inspirational songs performed by the winning groups from all three seasons, a compilation of lead singers from season three, a collegiate ensemble and special guests.