After their longest season yet, it was down to a college a cappella group, a hip hop group and a group creating an electronic dance club sound on the season finale of 'The Sing-Off' (Mon., 8PM ET on NBC). It was amazing watching these three powerhouse groups through the season.

!!SPOILER ALERT!!

The Dartmouth Aires soared under the powerful lead vocals of Michael, while it took Urban Method a little while to find their strengths beyond their rap niche. Pentatonix struggled a bit with deciding how far to take their signature remixes. But all three groups excelled and impressed week after week.

It was Guilty Pleasures night on 'The Sing-Off' (Mon., 8PM ET on NBC) and Ben Folds certainly got into the spirit of the theme. While his professional work has never delved into hip-hop or rap, Urban Method's take on Bell Biv Devoe's 'Poison' inspired him to lay down some rhymes.

Maybe he was just excited that all ten remaining groups were finally together in the same week -- we know we were! Or it could be that Urban Method absolutely killed that performance, proving once again that a cappella can do anything, and sometimes the most unexpected directions bear the most exciting fruit.

One thing we did learn. While we applaud Folds for digging very deep and finding his inner MC, he should probably stick to singing. It seems to suit him better.