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S6 E13- Bad News. Lily and Marshall see a fertility specialist, Dr. Stangel who is Barney's actual doppelgänger.
Ahhh, yes, the Marshall-i'm-gonna-teach-you-how-to-live episode. That would be the same episode as Lily & Marshall got back together, and Barney almost scored with twins, oh, and Barney "Gave my twin sister chlamydia, you slime"....... Can't really remember any numbers though.......
In the Halloween episode of the TV show "How I Met Your Mother," Marshall has made a bet involving a homemade costume with Barney involving Lily's sex dreams. Turtle is Barney's costume for the bet. Barney ultimately loses the bet and has to wear the costume for a year.
Ted, Barney, Marshall, Lily, Robin
(2x16) Stuff
The one where Barney gets a cold.
Season 2, Episode 16, "Stuff." To irritate Lily, Barney puts on a one man show. At the end of the episode, it was clearly so irritating to Lily that Marshall delivers his second slap as a part of their slap bet.
It's a fake marriage Barney made up while his mother was sick watch episode "The Stinson's"
Say Cheese (Season 5, Episode 18).
Season 4, Episode 11 if I am not mistaken ;-)
The Bracket (Season 3, Episode 14).
Season 2 Episode 20 titled Showdown has Barney on the price is right. Barney is overjoyed to be on the game show because he believes that Bob Barker is his real dad.