This is a great video (http://www.youtube.com/watch?v=wsFTgirKXHk) by Ben Goldacre explaining some interesting stuff about Placebo. It's in the medical context but I think it's not too off-topic here. I've been following for a while Goldacre's great blog Bad Science (http://www.badscience.net) where usually he copies what he writes on The Guardian as a science columnist.