As the title suggests, this episode - from Season 9 - sees Rachel's other sister Amy (superbly played by Christina Applegate) show up on their doorstep and promptly begin to ruin Thanksgiving, mostly through acting just as spoilt and bratty as you'd expect from a Green sister. She also insists on calling Emma 'Emily'.
Elsewhere, Monica reluctantly agrees to use the good china, while Joey misses the Days of Our Lives Macy's Day Parade float. It's not a bad episode by any means, but its quality is noticeably lower than many of the episodes on this list.
The fight between Rachel and Amy is really well done, and there are a few smaller moments - Joey getting the red plate; Chandler then breaking the plates - of real humour, but the story isn't all that great (seriously Jill, where've you been the last nine seasons?), and it's not all that Thanksgiving-y.
Quote: Amy : "Hi Emma." Phoebe: "Phoebe." Amy: "That's a funny noise."