I'm speculating here, but one thing I can tell you guys with 100% confidence is that a trusted source of mine recently was accosted in a bar by someone who claimed to have just worked on a shoot for Ghostbusters 3 in the Windy City. 

Apparently the scene involved an actress being "slimed," and that was all they got out before coming to their senses about what's probably sensitive information.

I'm gonna go out on a limb and say that I think we'll be seeing a teaser trailer of some sort for Ghostbusters 3 at this year's Comic-Con.  The timing is right.  There were rumors it would start shooting this Fall anyway.  Come late July, don't be surprised about reports from giddy bloggers, journalists and fans recounting their experience of a brand new on-screen, live-action sliming leading into Ray Parker Jr.'s iconic '80s theme. 

We can dream, can't we?  To hold you over until this hypothetical event, check out the trailer for Ghostbuster starring Ernie Hudson after the jump.