Favorite Guest Star

I loved when Rosanna Arquette guest starred. She is one of my fave actresses and this is one of my fave shows and when you bring them together, I'm a happy camper. I recently heard she made her music video directorial debut, which is really cool. She worked with a Netherlands hip hop artist named Postman. You can see the music video here: http://www.youtube.com/user/sociallifemmus­ic#­pla­y/u­plo­a..­.EY­M. I think it's really cool.

Anyways, enough of my rambling, who were some of your guys favorite or memorable guest stars?