The ritual of the bachelor party — from both the male and female perspectives — was explored in the aptly named episode "Bachelor Party" on How I Met Your Mother on this night in 2012.
Anyone who has ever participated in one of these rituals has probably been told something to the effect of this: Only a chosen few have been asked to join in — if you are one of those people, you are either a member of the family or close enough to be one.
There were two bachelor parties on the night in question, and Barney (Neil Patrick Harris) tried to influence both.
The guys — well, mostly Barney, who believed, all evidence to the contrary, that he was the best man — had planned a somewhat untraditional bachelor party for the groom — Marshall (Jason Segel).
It's important to note that Marshall had been saying repeatedly that he did not want to have a stripper. He preferred what Ted (Josh Radnor) had in mind — attending a big boxing match and consuming a large steak.
But Barney manipulated things so there was a stripper at the hotel suite in Atlantic City that had been rented for the occasion. Well, he thought they were going to Atlantic City. They were actually going to a resort and casino in Connecticut, some 200 miles to the northeast.
All of which made what happened when they got there implausible — to say the least.
The stripper was there and proceeded to provide the entertainment she had been hired by Barney to provide — until she broke her ankle. Then she had to be taken to the hospital, causing the guys to miss the fight (the car radio ranted about what an historic fight it had been).
Marshall was furious with Barney and kept telling him that he was not the best man. Marshall wasn't even sure he wanted Barney to be at the wedding — especially after Barney accidentally set the hotel room on fire with one of his custom–made Cuban cigars.
Meanwhile, Lily (Alyson Hannigan) was the guest of honor at a bridal shower. Robin (Cobie Smulders) wanted to give Lily a memorable gift and originally planned to give her a see–through nightie, but Barney talked her into something else — a vibrator. He explained to Robin that all of Lily's friends would be there, and there would be a lot of drinking.
"You need to get her something daring," Barney said so that's what Robin did. It was a decision she would regret.
When Robin arrived at the party, she discovered that the guests were not all Lily's peers after all. Lily's mother was there. So was her maternal grandmother, and two of Lily's juvenile cousins. An older cousin was there, too. She was about to become a nun. Robin decided she didn't want Lily to open her gift and tried to prevent it several times, finally resorting to switching cards with another gift — which turned out to be from Lily's grandmother.
She was as surprised as anyone when, after Lily opened the gift, everyone found there was a vibrator in it. But then Lily's mother observed that the gift resembled one that had been given on an episode of "Sex and the City."
It was an entirely different party after that.
Everyone gathered at the bar where they habitually gathered, and the girls learned that Barney had ruined the bachelor party. Marshall was about to tell Barney he wasn't invited to the wedding when Lily intervened. When she had been living in San Francisco the previous year after her breakup with Marshall, Barney had flown out to see her, gave her a plane ticket to New York and told her she and Marshall belonged together. Thus, he had been largely responsible for their eventual reunion.
Until that moment, only Lily and Barney had known about that.
Touched by Barney's concern and ashamed of his own conclusion that Barney was selfish, Marshall named Barney a co–best man with Ted.
Just like a member of the family.
