Will tandem performances bring twice the excitement? Double the pleasure?

“Can You Duet” (7 p.m., today, CMT), a singing competition from the producers of “American Idol,” begins tonight. Thousands auditioned, but only 10 pairs will compete on the televised version of “Duet.” The judges and mentors include singers Naomi Judd and Big Kenny, and record executive Scott Borchetta. Lance Smith hosts.

• The Disney Channel gives its audience what it wants, or at least used to want, with a four-hour helping of sing-a-long and dance-a-long versions of “High School Musical” (6 p.m., today, Disney) and “High School Musical 2” (8 p.m.). Stars from the two smash cable hits, including Zac Efron, Vanessa Hudgens, Ashley Tisdale, Lucas Grabeel, Corbin Bleu, Monique Coleman, Olesya Rulin, KayCee Stroh, Chris Warren Jr. and Ryne Sanborn will be on hand to host.

• How would you respond to events that are quite literally earth-shattering? The two-part summer miniseries “Impact” (8 p.m., Sunday, ABC, concludes next Sunday) asks us to imagine life on Earth after a violent meteor shower rips apart the moon and sends it on a collision course toward Earth.

Fortunately, there are two very attractive astrophysicists on the job, Alex Kittner (David James Elliott), the strong-jawed and recently widowed father of two, and Maddie Rhodes (Natasha Henstridge), an old friend of Alex, who, like this movie, finds it difficult to gauge the relative importance of things. Should she be worried about the imminent destruction of the planet? Or be happy that Alex is single again? Maddie’s conundrum is rather small potatoes compared to that faced by German meteorite expert Roland Emerson (Benjamin Sadler). He’s saddled with a nagging fiancee who just won’t let the prospect of human extinction stand in the way of her wedding plans! Neither cheesy enough to be campy fun nor credible enough to take seriously, this mini leaves no impact at all.

• David Suchet returns as Poirot and Julia McKenzie will portray Miss Marple in six Agatha Christie mysteries running on “Masterpiece Mystery” (8 p.m., Sunday, PBS, check local listings), airing weekly through July 26. Tonight: “Poirot: Cat Among the Pigeons.”

Today’s highlights

• David uses a power outage to his advantage on “Kings” (7 p.m., NBC).

• A explosion at the dock strands survivors on “Harper’s Island” (8 p.m., CBS).

• Eli goes on a road trip on “Eli Stone” (9 p.m., ABC).

Sunday’s highlights

• Naturalist and TV veteran Sir David Attenborough narrates “Charles Darwin and the Tree of Life” (6 p.m., BBC America), a celebration of the importance of Darwin’s theories and discoveries on the 200th anniversary of his birth and the 150th anniversary of the publication of “On the Origin of the Species.”

• It’s so long, farewell, auf wiedersehen, goodbye for some contestants on the British musical competition “How Do You Solve a Problem Like Maria?” (7 p.m., BBC America).