Marshall walks in on Ted in his boxers and Robin in a robe. Uh oh, what's been going on with these two exes?
Barney grabs himself a beer while he talks to Robin and her and Ted's shared apartment.
Ted talks to Barney as he's busy cleaning the apartment. That's right, Barney still wears a suit even when cleaning.

How I Met Your Mother Season 4 Episode 12 Quotes

You're right, super hot lady that my wife keeps telling me why you're famous but I keep forgetting

Marshall [to Kim Kardashian]

Barney: So I explained to her, I said Madelin, every single international conflict essentially boils down to sexual tension
Ted: Every international conflict?
Barney: Every single one, dude
Ted: So the crisis in the middle east could be solved by?
Barney: Gaza Strippers. Next.
Ted: Apartheid?
Barney: Apart Thighs? What else you got?
Ted: Cold war.
Barney: Ms. Gorbachev, Take Down Those Pants