Tuesdays Best Bets on TV

"American Idol" (8 p.m., Fox): More bad singers!
"Ancient Discoveries" (9 p.m., History Channel): Forget those textbook descriptions of centuries-old societies and their supposedly simplistic technologies: This new series examines clues that suggest more progressive inventions. For instance, the program says, mechanical water-fetching "maids" were invented in the third century, long before Roomba the robot vacuumed carpets. Phil Crowley narrates the series, which spotlights sophisticated machines and weapons of warfare, among other surprisingly ancient ideas. Tonight's episode reconstructs the legend of Troy.
"Veronica Mars" (9 p.m., the CW): In the latest episode of "Veronica Mars," Veronica finds something to take her mind off Logan: She takes a job helping animal researchers to track down a missing monkey.