Pairs sing it out on CMT’s ‘Duet’

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

“Can You Duet” (8 p.m., 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” (7 p.m.) and “High School Musical 2” (9 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.

•Cartoon Network continues its curious foray into live-action programming with “Destroy Build Destroy” (8:30 p.m., ).

As the title suggests, teams compete to build and demolish creations concocted from junkyards.

•How would you respond to events that are quite literally earth-shattering? The two-part summer miniseries “Impact” (9 p.m., Sunday, ABC; concludes June 28) asks us to imagine life on Earth after a violent meteor shower rips apart the moon and sends it on a collision course toward our planet.

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?

Neither cheesy enough to be campy fun nor credible enough to take seriously, it leaves no impact at all.

•Don’t go looking for beards, long hats and dusty owls in the new incarnation of “Merlin” (8 p.m. and 9 p.m., Sunday, NBC, TVPG).

This action-fantasy summer series follows the wizard as a young man (Colin Morgan) and features a young, attractive cast portraying the teenage versions of the Knights of the Round Table and other Arthurian characters.