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.
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When will viewers meet the mother of Ted's kids? Perhaps in the show's 100th episode.
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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.
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How I Met Your Mother Season 4 Episode 18 Quotes

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

If I could nail any celebrity it would definitely be Scarlett Johansson. Hot, talented and nobody does that many woodie allen movies without some serious daddy issues

Barney