If “MythBusters” (8 p.m., Discovery) were a movie, it would be “Revenge of the Nerds.” Hosts Adam Savage and Jamie Hyneman take demented glee in applying hard science and technical know-how to deconstructing urban legends. On tonight’s episode, they take on Hollywood and question the plausibility of well-known stunts and illusions.

How many times have you seen a hero plunge from a tall building only to have his fall broken by an awning? The “MythBusters” team makes good use of a hapless dummy testing this notion. And have you noticed how many times a movie swordfight ends with one sword hacked in half by the other? Is this really possible? Can steel cut steel? The “Mythbusters” break out an arsenal of clashing daggers, from Samurai swords to blunt Viking instruments. The boys also question a number of car-stunt scenes from films including “Austin Powers” and “Dukes of Hazzard.” Then they settle down to fun with firearms. Can you escape danger by firing a ring of bullet holes into the floor below you and falling to safety? Should you even try?

¢ The hunt for sexual predators continues on “Dateline” (7 p.m., NBC). On a second “Dateline” (8 p.m.), Matt Lauer interviews a teacher who had an affair with a 14-year-old boy. Fox has been running “Cops” for 18 seasons. NBC is fast turning “Dateline” into a new cinema-verite series called “Creeps.”

Tonight’s other highlights

¢ A recording star emerges on “Rock Star: Supernova” (7 p.m., CBS).

¢ Competition continues on “Dancing with the Stars” (7 p.m., ABC).

¢ A shroud of suspicion falls on a victim’s girlfriend on “Bones” (7 p.m., Fox).

¢ A runaway bride’s murder is blamed on a bartender close to Ron on “Justice” (8 p.m., Fox).

¢ ABC looks at the season ahead on “Sneak Peek” (8 p.m., ABC).

¢ A former “American Idol” star portrays herself in the 2006 cable biopic “Life Is Not a Fairy Tale: The Fantasia Barrino Story” (8 p.m., Lifetime).

¢ Ring tones can be murder on “CSI: NY” (9 p.m., CBS).

¢ “Modern Marvels” (9 p.m., History) looks at copper and its uses from ancient times to the present.

¢ Nobody has yet sewn up the competition on “Project Runway” (9 p.m., Bravo).

¢ “Inside the NFL” (9 p.m., HBO) enters its 30th season of pigskin prognostication.