The best of what's on TV tonight, including new episodes of "How I Met Your Mother" and "Revolution," and not "Monday Night Football."

The Sing-Off (NBC) — Contestants from throughout "The Sing-Off"'s three seasons return to croon their favorite holiday songs.

It was 30 years ago tonight that Howard Cosell announced the death of John Lennon during the final moments of regulation during a Monday Night Football game between the Dolphins and Patriots (above is Cosell's 1974 interview with Lennon, the MNF clip with the announcement is here).