Firefly references on Castle

I have begun watching Castle (in rerun) and have a chuckle every time there is a Firefly reference made. Nathan Fillion always gives a little smirk/wink.

Season 4, episode 16 - Setup: Martha asks Castle if he has heard about "Serenity" (a spa in the catskills)

Season 2 episode 6 - Vampire Weekend: Castle puts on his Halloween "costume", a space cowboy, the same he wore in Firefly ("like 5 years ago", as Alexis says - the entire dialog is hilarious).

What (if any) are some other episodes (season and number) with references to Firefly?

Best Answer

Here's a bunch.

Yes, it's a short answer, but this is probably what the OP was after. It's not complete but it's certainly fun. I did not transcribe the link because it's been around over two years and I don't anticipate it being gone anytime soon. If anything, I hope it's updated. Also because I haven't watched Castle and do not care to research where every quote came from during its run thus far.

"...didn't you wear that like, five years ago?" is by far my favorite, with the Chinese bit after it from "a TV show I used to love" being a close second.

This clip is similar, but has the Firefly instances to compare.

EDIT: Undeleted post to make answer per @WayneWeibel's request.