The history of science is replete with discoveries that were considered socially, morally, or emotionally dangerous in their time; the Copernican and Darwinian revolutions are the most obvious. What is your dangerous idea? An idea you think about (not necessarily one you originated) that is dangerous not because it is assumed to be false, but because it might be true?
I was immediately intrigued, seeing as how it's a large group of smart people talking about science, so I thought I'd give it a brief read and put it up here as a link for other like-minded folks to check out. It's been two days and I haven't been able to get through it. Not because it's boring, or because I don't like it: because it's a hard read. With such challenging and controversial ideas as "Government is the problem not the solution", If patterns of human love subtlely change, all sorts of social and political atrocities can escalate", "The fight against global warming is lost", and "No more teacher's dirty looks" (or put another way, "school is bad for kids"), reading more than two or three of them at a time gives me a headache. There's some interesting stuff there, though, and if you're one for expanding your worldveiw and challenging your preconcieved notions about things, then I highly recommend it.