How I Met Your Mother, 8 p.m., CBS
As we head into the last month of this show, it's finally the morning of Barney and Robin's wedding. Barney wakes up to the effects of the previous night's hearty partying, natch, and his friends scramble to figure out how to make a Stinson Hangover Fixer Elixir. Oh, HIMYM. We're going to miss this.
SEASON PREMIERE The Voice, 8 p.m., NBC
Usher and Shakira, who filled in for Cee Lo Green and Christina Aguilera as coaches in Season 4, are back again along with Adam Levine and Blake "I swear this isn't alcohol in my Starbucks cup" Shelton as the singing competition returns for a sixth time. One or both of the the new judges might be pulling full-time duty soon: Green announced last week that he's done with The Voice for good, and Aguilera is preggers. Also worth noting: Shakira's adviser this season is country star Miranda Lambert, a.k.a. Blake Shelton's wife.
SERIES PREMIERE Late Night With Seth Meyers, 12:35 a.m., NBC
Seth Meyers takes over Jimmy Fallon's old show now that Fallon has moved to 11:35 p.m. We like Meyers just fine, but we're more excited to see how Saturday Night Live alum Fred Armisen is as bandleader. Is this all an elaborate Ian Rubbish joke?
NCIS: Los Angeles, 9 p.m., CBS
A retired assassin played by guest star Danny Trejo becomes a suspect in a diplomat's murder. Take note, other CBS procedurals: All shows are better with Danny Trejo.
About a Boy, 9 p.m., NBC
This new NBC comedy moves to its actual time slot this week after a post-Olympics premiere Saturday. We're sure lots of great things happen in this episode, but we can't move past this part of the description: someone is "invited to a pool party hosted by rapper Lil Jon (guest starring as himself)". Okay then!
SERIES PREMIERE Mixology, 9:30 p.m., ABC
Set in New York's trendy meatpacking district, this new sitcom follows 10 singles spending an evening in a high-end bar. Hang on, is the meatpacking district still considered "trendy"? Wasn't it the It Spot when Samantha on Sex and the City moved there like 15 years ago?
Scandal, 10 p.m., ABC
Scandal is baaaaaaack! It's been more than two months since Olivia (Kerry Washington) and Co. have wreaked havoc on D.C. and the show's trench coat budget, and we're getting antsy. Tonight, Sally Langston (Kate Burton) is up to no good again, with an announcement that has the White House reeling. Gee, I wonder what she could possibly have to — oh, that's right, this is the lady who killed her husband!
Parenthood, 10 p.m., NBC
Crosby and Jasmine move in with his parents while their home is being repaired, Drew talks to his sister about girls, and we can't focus on any of that because we're still too sad about the Joel-Julia split.
SEASON PREMIERE Kitchen Nightmares, 8 p.m., Fox
In the season premiere of this Gordon Ramsay-hosted "reality" show, the chef returns to Amy's Baking Company. Avid watchers might remember it as the place he walked out of last season because the couple who owned it were pains in the, well, you know. Come on, don't you people know never to cross Ramsay? He will destroy you with his British sarcasm!
SEASON PREMIERE Hannibal, 10 p.m., NBC
All you really need to know about the second-season premiere is that Sex and the City gal Cynthia Nixon is joining the show in a recurring role as FBI agent Kade Purnell.