“How I Met Your Mother” (8 p.m., CBS): The fifth season of “How I Met Your

“How I Met Your Mother” (8 p.m., CBS): The fifth season of “How I Met Your Mother” gets under way as the gang discovers that Barney and Robin are a couple. This can’t last, can it?

“House” (8 p.m., Fox): “House” kicks off its sixth season with a two-hour episode that finds our tormented doc detoxing in a mental hospital and trying to escape. Andre Braugher guest stars.

“Dancing With the Stars” (8 p.m., ABC): Let the ballroom blitz begin. “Dancing With the Stars” returns with a new group of happy hoofers, including, among others, Tom DeLay, Donny Osmond, Melissa Joan Hart and Natalie Coughlin.