In this game the players improvise a dialogue along the lines of the famous "Quelle Coincidence!!" dialogue in Eugene Ionesco's "La Cantatrice Chauve" (see the opening lines below).
In pairs, one person initiates the conversation as if it is the first time s/he is meeting the other. The first line is, "Haven't I met you somewhere before?"
In the spirit of "yes, and...", the second person agrees and adds some new detail, e.g., "Yes, I was thinking the same thing, maybe at the horse track?"