This question about Charm Person got me musing about a problem with the spell. Obviously, you can't cast Charm Person in the middle of a forum to sway an interlocutor to your side without the other 20 persons noticing the foul play. And yet, I'd find it incredibly cool if it was somehow pulled off in a game.
My question is thus : Is there any mean to covertly cast a spell in d&d3.5 / Pathfinder ?
I've thought about Quicken Spell but nothing in the feat description indicates that you're not noticeable in doing this (as the spell still "takes an action", be it a swift one).