From my understanding, it was supposed to be a one-week event? Although, they started playing Ghostbusters on August 29th and my theater is playing it until September 11th. So I guess that makes it a two-week event.
Yes I agree, if you haven't seen it on the big screen, do it! Even if you've seen it a million times, you'll likely spot subtle jokes and visual gags you never noticed... giving a movie your undivided attention with a massive screen and loud sound means you really get to pick up on everything.
Personally, I don't know if I'll have the time to see it in the theater this year. Sorta trying to get this redesigned website finished.
But don't feel bad, because my local theater plays classic movies and they did Ghostbusters just about a year ago! So I've already gotten the theater experience. And after the passing of Harold Ramis earlier this year, I watched it again on bluray. So I'm not hurting for Ghostbuster viewings. I'll likely watch it at home sometime before Halloween too.