Rae of light

Issa Rae is still starving for affection in the third season of “Insecure,” although the dude who throws up in her Uber is awfully cute. Look for appearances this season from Regina Hall, Sterling K. Brown and singer Hayley Kiyoko.

9:30 p.m. Sun., HBO

Sex as a weapon

A formerly overweight teenager (Debby Ryan) seeks revenge on bullies via the beauty-pageant route in “Insatiable,” a sassy new sitcom that plays out like a telenovela with a decidedly Southern accent. Ryan, a former Disney Channel regular, doesn’t hesitate to show she’s all grown up, a transformation that may startle those who still picture her as the title star of “Jessie.”

Now streaming on Netflix

Once and future king

Those who believe King Arthur was an early incarnation of Harry Potter may be disappointed by the second-season premiere of “Sacred Sites,” but the documentary uncovers some fact-based revelations that are nearly as mind-blowing as someone yanking a sword out of a stone. Upcoming episodes will spoil bedtime stories about the Maltese, Nazis and Egyptian priestesses.

7 p.m. Mon., Smithsonian

Neal Justin