There are many Less Wrong posts I'd like to write, but I'm starting to admit there are some of them I'll probably never get around to. I need to be doing other things. If anybody wants to write up the post ideas below, go for it! You may also want to announce you're working on one or more of them in the comments, to avoid duplicate work.

In no particular order...

1. The Value of Information. Less Wrong still doesn't have a tutorial on how to do value of information calculations. If 5+ examples from common circumstances are included, I think this could be useful to many people. One classic example is that most people don't spend even 10 hours figuring out how they should spend several years of their life while getting a degree. [Update: Vaniver wrote this one.]
2. Gamify Boring Tasks. The potato chip lady is a classic example of how to do this. I've got several of my own examples from my own life, and perhaps another author has their own. "Make it a game" is something my mother might advise for getting through boring tasks, and I didn't take this advice seriously until lots of scientific literature gave me the same advice. ('Flow' literature.) This is one tiny piece of How to Beat Procrastination that could be zoomed in on with its own post.
3. Biases in Charity. We've all heard about scope insensitivity, but several other biases effect our charitable giving. This post could basically be a summary of this article, plus a few others from that same book. [Update: done by Kaj.]
4. Motivational Externalism. One of the classic debates in metaethics/moral psychology is between motivation externalism and motivational internalism. This debate seems to be in the process of being resolved by neuroscience, in favor of motivational externalism. I have spoken with LWers who do not know this. Much of the case is laid out here, though there are more details to be gleaned from neuroeconomics.
5. The Dr. Evil Problem. Less Wrong has spent much discussion on the sleeping beauty problem (due largely to Adam Elga). A similar problem in decision theory / probability theory that may be worth discussing is Elga's "Dr. Evil Problem," discussed here and here.
6. Hedonomics. Hedonomics is a particular way of combining decision research and happiness research, and has implications for scientific self-help. A beginning review is here. The field could be summarized for Less Wrong.
7. Thinking Too Little or Thinking Too Much. Thinking errors can result both from thinking too little (heuristics and biases) and from thinking too much (overzealous decision analysis). It would be useful to have some heuristics available to recognize which type of thinking error is likely under which circumstances, as discussed by Ariely & Norton (2010).
8. How to be a Happy Consumer. There is a ton of research on how to spend money in ways that actually make you happy, recently reviewed here. This could be summarized for Less Wrong.
9. Informal Fallacies as Errors in Bayesian Reasoning. Just as science errs or succeeds as it agrees with probability theory, informal fallacies are justified only in so far as they agree with Bayes. A recent summary of this is here. [Update: done by Kaj.]
10. Close-Call Counterfactuals. This is one of the biases I don't think has been discussed on Less Wrong yet. Summary. [Update: done by Kaj.]
11. Make Better Decisions with UnBBayes. UnBBayes is a fairly mature, actively developed cross-platform decision network software. It would be useful to have a tutorial on how Less Wrongers can use it to make better (important) decisions, like these video tutorials but with better real-life examples.