What to Watch Tonight: Two and a Half Men's Series' Finale and the Premieres of Vikings and CBS's Odd Couple Reboot

What to watch on Thursday, February 19...

7:30pm, Cartoon Network
Adventure Time
"Dark Purple" sends Susan Strong and her cadre on a mission into the Super Porp factory. But will they have time to get in, get out, and stop by the gift shop?

U.S. SERIES PREMIERE, 8pm, BBC America
QI
Stephen Fry hosts this panel show, which rewards its celebrity guests for their most scintillating contributions. The topics of tonight's first three episodes are journeys, people whose names start with "J," and jeopardy. Rhys Darby, Katy Brand, and Jeremy Clarkson are among the guests.

8pm, CBS
The Big Bang Theory
Howard is hit with a bombshell, Penny teaches Sheldon to roll with the punches, and Stuart prepares to reopen his shop in "The Comic Book Store Regeneration." As for Leonard and Raj, they're busy wondering whether that was really Nathan Fillion they spotted in a restaurant. I mean, do TV stars eat? Do Canadians?

8pm, The CW
The Vampire Diaries
Caroline assigns tasks to each of her friends (which is the Carolinest logline possible), but her behavior in the wake of Liz's passing concerns Elena. Elsewhere in "Let Her Go," Damon grapples with painful memories of his mother, Kai's latest move raises red flags for Alaric, and Matt and Tyler consider a major life change, thus launching a dozen fanfics before I even finished this sentence.

8pm, ABC
Grey's Anatomy
Meredith dodges Maggie's questions about D.C., Arizona finally gets on Dr. Herman's good side, and Richard suspects that Catherine is playing him. Meanwhile in "The Great Pretenders," Ben and Bailey fret when Ben's brother is admitted to the hospital.

8pm, NBC
The Slap
The perspective shifts to "Harry," who receives a visit from the police about the whole assaulting-a-minor thing. Hector tries to convince Harry to apologize to Gary and Rosie, but since this show has another six episodes to fill out, that plan goes awry.

SERIES PREMIERE, 8:30pm, CBS
The Odd Couple
Slovenly Oscar Madison (Matthew Perry) welcomes fastidious Felix Unger (Thomas Lennon) as his new roommate in the latest incarnation of the 1970s sitcom based on Neil Simon's play.

SERIES FINALE, 9pm, CBS
Two and a Half Men
Will Charlie Sheen return for the venerable sitcom's hour-long swan song? Is Charlie Harper truly dead? Could he be, in fact, alive? The title of the series finale is "Of Course He's Dead," which would seem to settle things. I've never known a sitcom episode title to lie to me, have you?

9pm, ABC
Scandal
Team Olivia pulls out all the stops to bring their captured leader home safe and sound in "No More Blood." However, optimism about her return is in short supply at 1600 Penn.

9pm, The CW
Reign
In "Forbidden," Mary's mother arrives bearing warnings, as well as a nice haggis from back home because Mary looks thin and are they even feeding her in France? As Mary takes bold action against the threats to her throne, Francis takes bold action of his own with Lola.

9pm, NBC
The Blacklist
A polygamous cult leader goes missing in "The Kenyon Family," spurring the team to investigate his property and the dangerous items therein. Red is on a mission of his own, hunting for the hidden safe that's sure to hold Al Capone's treasure or Curly's gold or the Hookshot or something equally awesome.

9pm, Fox
Backstrom
The team races to rescue an abducted teenage girl in "Bogeyman," though Backstrom is haunted by an old unsolved case whose victim bore striking similarities to the girl they're searching for. In other bad news, Det. Sgt. Almond's church may be shut down thanks to his falling behind on the rent.

SEASON 3 PREMIERE, 10pm, History
Vikings
Ragnar and Lagertha lead their forces into the fray once more in "Mercenary," while King Ecbert has a proposition for the Norsemen.

10pm, CBS
Elementary
A spate of murders in "When Your Number's Up" are tied to matters of wrongful death compensation. On the personal front, Sherlock extends a crucial kindness toward a grieving Joan.

10pm, ABC
How to Get Away With Murder
A guilt-ridden Annalise seeks assistance in "Mama's Here Now." Meanwhile, Bonnie takes on a new client who's facing a rape accusation.

10pm, Pivot
Fortitude
While Frank faces the fact that the evidence is stacked against him, Elena is plagued by the return of past demons.

10pm, FX
Archer
In "Nellis," a rescue mission leads the team to Area 51. The hardest part will be getting Krieger to leave.

10pm, NBC
Allegiance
Alex and company scour the City of Brotherly Love for Mikhail's hidden laptop in "Surreptitious Entry," and if you don't think he's gonna run up the steps of the art museum humming the theme from Rocky when they find it, you've got another thing coming. Elsewhere, Natalie is backed into a corner after Katya stumbles upon a vital secret.

10pm, IFC
Portlandia
Doug must reckon with the horrifying truth that he values gender equality in "Doug Becomes a Feminist." In other eye-opening developments, Sandra takes her first Rideshare.

LATE-NITE:
– The cast of Hot Tub Time Machine 2, Ronda Rousey, and Hanni El Khatib on Conan, 11pm, TBS
– Patricia Arquette on The Daily Show with Jon Stewart, 11pm, Comedy Central
– Martin Short, Ruth Wilson, and Walk The Moon on The Tonight Show Starring Jimmy Fallon, 11:35pm, NBC
– Don Cheadle, Ilana Glazer & Abbi Jacobson, and Mikky Ekko on Late Show with David Letterman, 11:35pm, CBS
– Kelly Ripa, Joshua Malina, and Gorgon City featuring Jennifer Hudson on Jimmy Kimmel Live, 11:35pm, ABC
– Mae Whitman and Carolina Herrera on Late Night with Seth Meyers, 12:35am, NBC
– Ray Romano, Busy Philipps, Tom Papa, and guest host Lauren Graham on The Late Late Show, 12:37am, CBS

WHAT ARE YOU WATCHING TONIGHT?