The third episode of Downton Abbey will be aired by PBS Masterpiece Classic at 9 PM on Sunday. You can join in a twitter discussion as the episode airs by using PBS's TweetGrid, which will automatically add the hashtag, #DowntonPBS.
Sybil and her new dress
The discussion will begin from 9 PM EST through 10:30 PM PT. Others who might join in at various times are the following Twitterers: