I guess that usually, we have to wonder why they make sequels. If nothing else, as long as the sequels aren't boring, obnoxious, pathetic, embarrassing, insulting, or otherwise bad, then they're acceptable. "Ghostbusters II" passes. Bill Murray, Dan Aykroyd, Harold Ramis, Ernie Hudson, Sigourney Weaver, Annie Potts and Rick Moranis reprise their roles from the original. This one has the title characters battling a river of hostility-based slime that's possessing a painting. Peter MacNicol plays the man who brought the painting to New York, and subsequently gets possessed by it. "Ghostbusters II" is pretty ridiculous, often gross, but never unpleasant. So who you gonna call?