As Kahneman points out in his new book, failures of reasoning are much easier to recognize in others than in ourselves. His book is framed around introducing the language of heuristics and biases to office water-cooler gossip. Practicing on the hardest level (self-analysis) doesn't seem like the best way to grow stronger.
It's one thing to read about a subject, but one gains a deeper understanding by seeing it applied to real problems, and an even deeper understanding by applying it yourself. This applies in particular to the closely related subjects of rationality, cognitive biases, and decision theory. With this in mind, I'd like to propose that we create one or more discussion topics each devoted to discussing and analyzing one decision problem of one person, and see how all this theory we've been discussing can help. The person could be either a Less Wrong member or just an acquaintance of one of us.
I'll commit to actively participating myself. Does anyone want to put forth a problem to discuss?