Here is one on changes in the placebo effect.
Here is one from mzrowan on the decline effect. which also led me to an article on why most published findings are false. (Fair warning, I found the second one harder to read and a little bit ranty.)
I also read this interesting article on atheists and what it would take to get them to change their positions.
The idea is that atheists are accused of being close-minded but that they feel that it is theists who are close-minded, eg, that we theists often openly admit that nothing would change our beliefs. The writer asked for theist responses, examples of things that would change their minds. When they did they were... kind of mocked and deconstructed, which I suppose makes sense (and some of the responses were in fact pretty silly).
I found this to be an interesting idea. I guess my perspective is that the atheistic position described here is based on logic, rationality. Nothing wrong with that, but I don't think those things are a big factor in most people's belief systems. I know they aren't in mine. I'm a pagan because it works for me and I would likely go on being a pagan even if I became an atheist as well. (There are pagan atheists and agnostics just like there are pagan buddhists and judeopagans.) I guess the only reason I can imagine leaving paganism would be if it no longer worked for me and I had good reason to think it would never work again. No longer being a source of support in my life, but rather a drain on my resources. Which has little to do with logic or proof, or even much of anything about the world outside of my head, and I feel pretty okay about that. From my perspective, that piece of writing has a good point but is pretty orthogonal to how I see my spirituality.