Over the last week or two, I've been rewatching the first 5 seasons of Sopranos and noticed a coincidence that cracked me up a little. In season 3, Tony Hale (Buster in Arrested Development) has a non-speaking role as the doctor administering Junior's chemotherapy. Just a handful of episodes later, in season 4, Will Arnett (Gob in Arrested Development) plays the boyfriend of the FBI agent working undercover to flip Adriana.

Another recent coincidence I noticed was the prominence of HBO series members in the Miami Vice movie. Among the cast: Ciaran Hinds (Julius Caesar from Rome), Justin Theroux (Joe from season 4 of Six Feet Under), John Hawkes (Sol Star from Deadwood) and Pavel Lychnikoff (Blazanov from Deadwood) all had minor speaking roles.

So what coincidental castings have others noticed or found amusing?

How about all the guys and gals from OZ that have ended up on one of the Law & Order shows.

^ and two more of the Oz guys on Lost.

Bradley Whitford and John Spencer from the West Wing in the movie Presumed Innocent. Granted this was way before the show, but I think it still applies.

Herc from The Wire & Entourage ( Dom ) was in Miami Vice also.

George Clooney in both the half-hour sitcom AND one-hour drama version of ER.

What are the odds......

(Patiently waiting for someone to point out some stunt casting as a "coincidence")

I don't know if it's a coincidence, but I always thought it was weird when an actor who appears as a guest star in one episode comes back as a series regular as another character.

Dennis Franz in Hill Street Blues
Harry Morgan on MASH

John Mahoney played a songwriter on Cheers. You'd think Frasier might have said something like "Gee, you look just like my dad!"

Law & Order has done this more than any other show, all I can remember right now is Jerry Orbach and Ice-T, but there are a couple more.
Of course Garret Dillahunt did this about 12 times on Deadwood.

Nicholas Lea on The X-Files

"Beer and pretzels, that's our game. C-H-E-R-S"

Oh, I've just thought of another one : Mary Lynn Rajskub who is seen every week as formerly annoying but now beloved as Jack Bauer's CTU co-worker Chloe on 24 was first noticed playing David Spade's completely annoying co-worker and love interest on Just Shoot Me. Her name? Chloe.