... you have half-written the first draft of a screenplay and then see a trailer for a movie that's in post production which has pretty much the same theme?
Yeah, me too. Knights of Badassdom is a soon-to-be-released film where a group of (US) live role-players summon a Succubus and have to deal with her. You can see the YouTube clip with the previous link. Sound familiar? Well, it does to me.
My screenplay-in-progress Dead Role-Players has a similar theme where a group of (UK) live role-players summon demon and have to deal with it. Bugger. Still, my finished screenplay is a long way off and (hopefully) by the time when it's anywhere near sending out it may be time for another LARP-based horror-comedy. Maybe.