Frasier actors in other shows

I recently spotted Marsha Mason (Sherry Dempsey) in an episode of The Middle. It got me thinking about other shows the stars of Frasier have been in.

Kelsey Grammer in Boss, and Transformers. David Hyde Pierce in The Perfect Host. I've been informed that he's in some episodes of The Good Wife (A show my father in law watches).

Have any of the Frasier actors (Even minor ones) ever unexpectedly popped up in a show you've been watching?

I've been watching a show called Medium on Netflix and have seen a couple of actors from Frasier (which doesn't surprise me given that Kelsey Grammer is a producer of the show). Both Kelsey Grammer and Peri Gilpin have appeared as gues actors. Interestingly, in one scene where we here the TV running in the background, the show that's playing is an episode of Frasier!

Haha that must have been fun!

I'll always remember the episode of Seinfeld when Jane Leeves (Daphne) appeared as Seinfeld's date who swore not to have sex before she got married... only to go off and sleep with John F. Kennedy Jr.