Overview
"Double Date" is the second episode of the fifth season of the sitcom How I Met Your Mother, and the 90th episode overall. It originally aired on September 28, 2009.
Plot
Future Ted describes a date he went on in 2009, and the screen quickly changes to show a side-by-side shot of him preparing in 2009 and 2002. It turns out that Ted is about to go on a blind date with Jen, a woman he went on another blind date with in 2002. After going to exactly the same restaurant and exchanging the same dialogue, including a pun about shellfish that Jen describes as "really bad", Ted and Jen realize they are repeating their blind date from seven years ago. They remember that the date was horrible, from Ted's snobbish behavior to Jen's obsession with her cats and her ex-boyfriend. Frightened by the prospect of having to date everyone in New York City again, they decide to retrace their steps to find the mistakes of the first date.
Learning new things about themselves on the first date, Ted and Jen head to MacLaren's, where the gang is there to help them retrace the events of the 2002 date. Jen reveals that she thought Ted was checking out a woman at the bar, when Ted and Barney were really looking at "Mustache Marshall". Ted and Jen head up to the roof, and after they share a kiss they suddenly realize why they never had another date: Ted never called her. Ted apologizes for his blunder and gives a version of what might have happened had they gotten together. Before Ted and Jen can kiss again on the roof, he stops and realizes that their quirks are part of who they are and that they should hold out for someone who will not just tolerate them, but like them. Future Ted then tells his kids that when he told the shellfish pun to their mother, she laughed (almost completely sincerely).
From Wikipedia (CC BY-SA 4.0).