identifying content based v. content neutral limits on speech in public forums:
i)    if the gov’t charges a permit fee => okay, but if they charge different permit fees depending upon the type of speech (or listener’s reaction to speech) => content based  Forsyth Cty.
ii)    If we open up gov’t water plant for a recycle day, can we keep out PETA?  Yes, if rzbl b/c we haven’t converted the plant to a public forum by opening for one day for recycling; this isn’t about speech; no one is expressing views.