Barney is, of course, a one-man meme machine. He's given the world so many catch phrases, including "Haaaave you met my friend Ted?" "Suit up!" "It's going to be legen... wait for it... dary." Of course, he also wrote the bro code, an ongoing list of man rules which flashes across the screen
Sorry, Robin. The group created a drinking game out of her on-air tendency to constantly say "but, umm.." between sentences.
Robin has a past as a Canadian pop star named Robin Sparkles, who is frequently revisited in flashbacks. Her greatest hit was "Let's Go to the Mall."
Ted stole a blue French horn for Robin in the pilot of the show, and every time it reappears it symbolizes his great love for her (and for romance).
The pals had an ongoing joke that when someone says anything that can be interrupted as vaguely related to the military, they each salute. See, for example, "major buzzkill."
The group of friends started out holding really serious interventions, like for a drinking problem, then used the same banner for fashion faux pas and the like.
Ted bought ill-advised red cowboy boots because he thought he could pull them off, and over the course of the series the shoes were worn by several characters and came to symbolize his wild singledom.
Toward the beginning of the series, Ted met a girl dressed as a slutty pumpkin on Halloween and thought she could be the one. He searched for years, and finally discovered her again—hi, guest star Katie Holmes!—but it turned out their chemistry was not so great.
One of the few details about the Mother that played out over the show was that she owned a yellow umbrella, which Ted accidentally stole at a party. Whenever the yellow umbrella appeared, that meant Mom was close by.
Ted had a mysterious drunken night in the first season and woke up with a pineapple on his nightstand. The show has yet to reveal how it got there—maybe in the finale!
"The Naked Man" is technique the gang uses to convince people to sleep with them. Turns out, if you just surprise people with nudity, they'll often give in and get it over with.
The goat was another wacky party appearance... until Future Ted used the animal to leap ahead and confess details about what was to come.
The group believes that every person in the world has a lookalike existing somewhere out there, and over the course of the series, viewers have encountered each character's doppelganger. Lily's is a stripper!
After winning a bet, Marshall won the right to give Barney five (and eventually eight) slaps. They can come at any time, with one slap still left to go in the series.