Oof, I'm rather cynical about chat events overall; the ones I've seen succeed emerge organically from the interactions of an active community, rather than starting with "we need a chat event."
However, you might try seeing if Literature is interested in partnering up for something.
Also Role-playing Games is starting up its own chat events with some limited success. Since RPGs are basically collaborative, improvised storytelling with an imposed structure, there might be some meshing available there.
(I think the scifi chat has regular movie-watching events, but I would think twice before yoking up to that ox.)