"The Sing-Off" is a televised singing competition that features a cappella groups from across the United States. Contestants perform popular songs without instrumental accompaniment, showcasing their vocal harmonies and arrangements. The show is judged by a panel of music industry professionals, who provide feedback and select the winning group. The series originally premiered in 2009 and has had multiple seasons, with each season culminating in a grand finale where the top groups compete for a cash prize and a recording contract. The show has helped popularize a cappella music and has inspired many viewers to explore this unique genre.