Sandy Petersen and Greg Stafford signed my Ghostbusters RPG! Both seemed genuinely happy to see the book, and I think they also liked the fact that someone is still playing it.
I saw people playing the Ghostbusters board game, but not the RPG (sadly). I tried to make up for this by using my Ghost die in an RPG I played in. I rolled a ghost several times, which in this game just meant a 6, and that was good! Happy ghost!
Here are some other fun Ghostbusters-related shots from the con.