Lily: Louise Marsh?! That's a whore's name if I ever heard one.
Marshall: Yeah, why would he want to get back together with Louise Marsh?
[flashback to young Robin talking with Simon:]
Simon: Well, the thing is, her folks just put in a pool.
Robin: Oh.
Simon: So...
Robin: Totally. I get it. Pools are great. Swimming's awesome. We have a sprinkler. Run right through it. Well, I should go.
Simon: Uh, babe, wait.
Robin: Yeah, Simon?
Simon: You forgot to load the drum set.