Greys Anatomy Season 6 Episode 23 (Greys Anatomy s06e23) with title “Sanctuary, Death and All His Friends” airs on Thursday, May 20th 2010 at 09:00 pm via ABC.
Here is summary for Greys Anatomy Season 6 Episode 23 :

A crisis hits Seattle Grace-Mercy West, testing Meredith and Cristina’s surgical skills. Mandy Moore guest stars.

Few hours after original series aired on TV, online streaming video for Greys Anatomy Season 6 Episode 23 usually available on Net and of course, if video available, as soon as possible will show you where you can watch this episode for free.