20 Mind-Blowing Facts You Never Knew About How I Met Your Mother

10. The Main Cast's Partners Are In The Show

On top of the cameos from famous musicians and the like, How I Met Your Mother also sees some more sentimental guest stars in the form of the partners of the main cast. They're not quite on the Brad Pitt in Friends level, but thanks to distinctive characters and recurring appearances they've became a central fabric to the show.

Sandy Rivers, the sleazy news anchor, is played by Alyson Hannigan's husband Alexis Denisof, whom she met on the set of Buffy; Taran Killam, Cobie Smulder's husband, played Gary Blauman, the gang dividing GNB worker; Scooter, Lily's obsessed high school ex, is played by David Burtka, Neil Patrick Harris' long term boyfriend and now husband. They all play pretty strongly against type (all three characters are pretty unlikeable people), which makes the cameos all the funnier.