Someone on the hackspace mailing list recently posted a link to a Harry Potter fanfic. Not something that I would normally jump at, but given the context and the recommendations that followed I gave it a look.
It was brilliant (and more than a little educational) - not to mention laugh-out-loud funny in many places. I read it while walking down the street, and in lieu of TV/games that evening, and so on until I finished all 70 chapters that have been written to date.
Harry Potter and the Methods of Rationality.
I've now moved on to reading the "sequences" of posts about rational thinking on the
Less Wrong website. I've certainly learnt more than I already knew about how to think rationally, although whether this has actually improved my thinking remains to be seen. When I'm done reading the base sequences I shall go looking for a place to test myself and exercise my reasoning/arguing skills. And then perhaps start taking a fresh look at my beliefs.
Of course I have always thought of myself as a rational thinker, but then so does everyone else...
It's a terrible shame that people vote and serve on juries without proper training along these lines.