Marshall: No, guys. I was walking home from work, through Central Park, and I stopped at the zoo.
[flashback to Marshall looking at the monkey enclosure:]
Park ranger: Watch it. Don't get any closer.
Marshall: Oh! It's cool. It's cool.
[The monkey pulls on Marshall's jacket and grabs his wallet]
[present:]
Barney: You're telling us...
Ted: That you got mugged...
Marshall: By a monkey. I got mugged by a monkey. [all laugh]