Boardwalk Empire Sunday at 9 p.m., HBO
The series returns for its fifth and final season with a very strong premiere. I have a feeling, after watching the first two episodes, that “Boardwalk Empire” may leave TV with one of its best strings of episodes so far, as they toggle between Nucky (Steve Buscemi, above) in 1931 and Nucky as a child. In 1931, we see him in Cuba trying to secure a deal with a rum magnate by the name of Bacardi, in anticipation of the repeal of Prohibition. We also see Chalky stuck in prison and Gillian in the weirdest madhouse ever. And in the flashbacks to Nucky’s youth, we see the start of his long relationship with the Commodore and get a sense of why he became such a strange dude.
Stand Up to Cancer 8 p.m.
This telethon, which I’m betting will not feature any ice bucket situations, will be simulcast live across many channels and streaming services, including CBS, NBC, ABC, Fox, Yahoo, and Hulu. Among those who’ll appear on the event, which is hosted by cofounder Katie Couric, are Jon Hamm, Jennifer Aniston, Halle Berry, Kiefer Sutherland, Ben Stiller, Will Ferrell, Mark Harmon, Marg Helgenberger (above), Rob Lowe, Danny McBride, Jesse Tyler Ferguson, and Dane Cook. And who will be performing. Yes, that’s what I mean. The Who will be performing.
Doctor Who Saturday at 9 p.m., BBC America
I’ve heard it was he who let the dogs out.
The Knick 10 p.m., Cinemax
Sister Harriet has a habit.
Brain Games 9 and 10 p.m., National Geographic
Mine likes Trouble, with the pop-o-matic, of course.Matthew Gilbert can be reached at email@example.com. Follow him on Twitter @MatthewGilbert.