Seen recently nuzzling Moe Szyslak on “The Simpsons” Christmas episode, Katy Perry is set to open “A Home for the Holidays” (7 p.m., CBS), the annual performance showcase and holiday celebration intended to raise awareness of children in need of adoption and the families that have been enriched by the arrival of adopted children. Other scheduled performers include Melissa Etheridge, Maroon 5, Ricky Martin and Nelly.

• They don’t climb every mountain, but they have climbed the pop charts. “Top Ten Monks” (7 p.m., HBO2) explores the curious stardom of an order of Austrian monks whose prayers sung in Latin as Gregorian chants have outsold Lady Gaga in many European markets.

The Cistercian monks of the Heiligenkreuz Abbey did not go looking for fame. It found them in the person of Tom Lewis, a persistent Universal recording executive who had noticed that sales of Gregorian chants from their back order had been on the rise. He placed ads in Catholic newspapers looking for new talent, and the monks of Heiligenkreuz were among the last to answer. Both Lewis and the order’s Father Karl think that fans of their CD “Chant: Music for the Soul” are looking for something different and beautiful in a world that offers too much commercial sameness.

After establishing their European fame and showing some of the monks sharing the couch on Germany’s version of the “Today” show (with a seemingly unamused Karl Lagerfeld), the film explores the world of a 12th-century order in the 21st century. Yes, the monks use cell phones, computers and have posted some of their “hits” on YouTube. They pray or chant more than six hours a day. Those looking for an austere existence will be surprised by the variety of work performed at the religious order. One monk confesses that he wrestled for a long time over the issue of chastity.

I would have liked to learn a little more about the music performed and the musicality of the order. But viewers in search of something a little different should not miss “Top Ten Monks,” a holiday offering that succeeds in introducing some moments of the sublime and transcendent into the din of the Christmas countdown.

• Syfy kicks off a holiday schedule of marathons with 16 hours of “Ghost Hunters” and “Ghost Hunters International,” beginning at 8 a.m.

Tonight’s other highlights

• Stolen currency on “Undercovers” (7 p.m., NBC).

• A deadly killer stalks the suburbs at Christmastime on “Human Target” (7 p.m., Fox).

• On two episodes of “Law & Order: Special Victims Unit” (8 p.m., NBC), a teen expires (8 p.m.), beaten and mutilated (9 p.m.).

• Kevin Pollak hosts “Million Dollar Money Drop” (8 p.m., Fox).

• A smoke detector rattles Phil on “Modern Family” (8 p.m., ABC).

• An arson case may result in a murder trial on “The Defenders” (9 p.m., CBS).

• The guys need help from Yang (Ally Sheedy) to capture Dr. Yin on “Psych” (9 p.m., USA).