15 Best How I Met Your Mother Episodes
7. Slap Bet (Season 2, Episode 9)
"Let's go to the mall!"
In what is arguably the show's most iconic episode, Robin tries to hide the reason she doesn't like shopping malls from her friends, causing Ted, Barney and Marshall to do some digging into her secret past. Slap Bet is full of shocking and hilarious revelations, and introduces fans to the titular slap bet, which would continue to play a big part in the show until the finale.
Up until this point, Robin has been shrouded in mystery. She comes from Canada, she works as a reporter, and that's about it. In a series of bizarre and funny sub-plots, in which Barney thinks she used to be a porn star and Marshall thinks she was once married, it is revealed that Robin used to be Robin Sparkles - a teen pop star in Canada who had a major hit called "Let's Go to the Mall."
The revelation comes complete with a full music video, and one of the funniest scenes in the show, as Cobie Smulders is seen dressing like an 90s pop icon and singing what might just be the world's worst song. It's brilliant through and through.