Monday’s TV highlights

SERIES

The Sing-Off: The remaining groups perform and the winner is named in the season finale (8 p.m. NBC).

Independent Lens: “The Calling,” which concludes Tuesday, follows American students from Catholic, Protestant, Jewish and Muslim faiths as they prepare to become ordained religious professionals (9 p.m. KCET).

American Pickers: A collector has filled a train station with vintage cars, but Mike is taken with a mysterious Italian trunk that hasn’t been opened in 50 years, and the guys stop at a New Hampshire home with a weather vane made from a real Harley-Davidson motorbike in this new episode (9 p.m. History).

The Closer: The squad’s holiday plans are jeopardized when a feud leads to a stabbing on Christmas Eve and the accidental death of a family’s patriarch in this new episode (9 p.m. TNT).

Hoarders: After growing up with a mother who was an inveterate hoarder, a 19-year-old man realizes he must get his own hoarding under control if he wants to have a “normal” life, in this new episode (10 p.m. A&E).

Men of a Certain Age: Joe (Ray Romano) finds himself dating two women, a situation he isn’t sure how to handle, and Terry (Scott Bakula) makes a bet with another salesman over which of them can move more cars in this new episode (10 p.m. TNT).

SPECIALS

Martha and the Christmas Tree: In the first of six planned episodes of this new animated series, 10-year-old Martha Stewart and her friends enter the annual Bedford Falls tree trimming contest (7 p.m. Hallmark).

MOVIES

The Special Relationship: HBO reprises some of its best 2010 TV movies beginning with Michael Sheen and Dennis Quaid in “The Special Relationship” (7:30 p.m.); Claire Danes and Catherine O’Hara in “Temple Grandin” (9 p.m.); and Al Pacino and Susan Sarandon in “You Don’t Know Jack” (11 p.m.).

SPORTS

Basketball: The Minnesota Timberwolves visit the Clippers (7:30 p.m. FS Prime).