Looking for a party planner for sis’ 30th b-day or a decent size venue to hold 30 ppl in Chicago… any ideas?

I’m trying to be real creative with my sister’s 30th surprise b-day party and would like to do some type of “Hollywood” or “Murder Mystery” theme where we have actors or the guest are the actors but have no idea where to start. I’d like to host it somewhere in downtown Chicago and plan on [...]