It appears that Michael Cera (Superbad, Nick & Norah's Infinite Playlist) wants a role in the third Ghostbusters film...playing Oscar, Sigourney Weaver's son. This is what Cera had to say to People Magazine.
(I loved) Ghostbusters! As a kid, I wanted to be Bill Murray's character. Harold told me lots of stories and I memorized every word.
Personally, I think the kid could pull it off -- and I think it's highly likely that he'll be considered for the role.