You want a crossover? I'll give you a crossover.

[Bob Schroeck]

Han Solo made several appearances in Firefly.
-- Bob
---------
Then the horns kicked in...
...and my shoes began to squeak.

[Black Aeronaut]

WHAAAT!? *Checks the link, then starts laughing hysterically*

Awwww man! That is awesome.

Even so, the idea has merit.

[Sweno]

neat!
-Terry
-----
"so listen up boy, or pornography starring your mother will be the second worst thing to happen to you today"
TF2: Spy

[Kurisu]

(Goes and digs out the Firefly discs)

Got to find them all...
_____
DEATH is Certain. The hour, Uncertain...

[Bob Schroeck]

Got to find them all...

No, no, that's Pokemon.
-- Bob
---------
Then the horns kicked in...
...and my shoes began to squeak.

[Kurisu]

5 confirmed sightings so far... still going.
_____
DEATH is Certain. The hour, Uncertain...

[Black Aeronaut]

Gawd dayum... Somebody on the production was a real SW geek.

[Rod.H]

Yeah, Nathan Fillion. It's apparently his Han Solo in Carbonite figurine, turned set dressing easter egg. Still doesn't he have a prop from Firefly rocking 'round his apartment set on Castle?

[Duane Peters]

He's got a bit more than just one prop in the apartment...
http://www.youtube.com/watch?v=3Q3pdj9p6yI
Oh, and the prop in the apartment? The catalyzer from the episode "Out of Gas", partially visible behind Fillion as he pops out of his bedroom and draws his gun, on the bookcase behind him just below waist level.