Conversation so far:
Who is Frank Rich?
Frank Rich of the New York Times.
What were the conversations about?
in connection with the Sondheim Celebration Sondheim.
What was the celebration for?
The Kennedy Center held a Sondheim Celebration, running from May to August 2002, consisting of six of Sondheim's musicals.

Question: Which musicals?
Self-contained rewrite: Which musicals were played at the Sondheim Celebration?