In this flashback after the credits, it turns out Robin was actually the one to suggest the Old King Clancey to her Canadian "celebrity" she went home with.
When will viewers meet the mother of Ted's kids? Perhaps in the show's 100th episode.
Barney helps teach Marshall how to keep up an elaborate lie in order for Ted not to find out he was fired from the GNB headquarters project.

How I Met Your Mother Season 4 Episode 18 Quotes

Ted: What is an ETR?
Barney: It's an Employee Transition Room.
Ted: What does that mean?
Barney: Well, it's a space where a supervisor and an employee engage in a knowledge transfer about an impending vocational paradigm shift.
Marshal: People get fired here

Ted: I just got screwed by my two best friends and I didn't even know it
Lily: In Canada that's called a sneaky snowflake