The plot of this How I Met Your Mother episode was simple:
Marshall gets mugged. He is kind of pathetic.
Lily's so freaked out that she says she's getting a gun.
To keep her from getting a gun, Marshall says he got robbed by a monkey at the zoo.
Marshall recants the story because he didn't want Lily to get the gun.
Robin loved the story so much, and was so desperate for an interview, she brings him on her show.
Barney is consumed by lying to girls and going to the most extreme lengths ever to do so.
Case in point? Saying he is Neil Armstrong.