Don't neglect non-sequence topics. Because they are self contained, I think they'd do better in lecture format without requiring tons of pre-requisite understanding.
Yvain's Diseased Thinking, Discussion on Excuses, Schelling Fences on Slippery Slopes are all understandable and cover real world issues. Anna Salamon's Learned Blankness, LukeProg's How to Be Happy, Swimmer963's Action and Habit and Eliezer's non-sequence posts 5 second level and Working hurts less than procrastinating, we fear the twinge of starting are all great self-contained posts about how to improve your life. (Also plugging my own punctuality post). And PhilGoetz's Reason as Memetic Immune disorder and Things you are Supposed to Like are both posts I wish I'd been able to read back when I was in highschool. I know there's tons of stuff I haven't even broached.
My point is that a lot of the best content exists outside of the sequences. Some of the highest value stuff is there, and they're all topics that can be covered in a 5-20 minute talk.
Just recently at my high school, a group of classmates and I started a science club. A major component of this is listening and giving peer lectures on topics of physics, math, computer science, etc. I picked a topic a bit off to the side: philosophy and decision making. Naturally, this includes rationality. My plan is to start with something based off the sequences, specifically "How to Actually Change Your Mind" and "A Human's Guide to Words".
I was hoping the Less Wrong community could give me some suggestions, tips, or even alternative ways to approach this. There is no end goal, we just want to learn more and think better. All our members are among the top 5% academically of their own grade. Most of us are seniors and have finished high school math, taking AP Calculus this year. We have covered basic statistics and Bayes' Theorem, but only applied it to the Disease Problem.
Any help or ideas are appreciated.
Update: Thank you for all these suggestions! They are incredibly helpful for me. I will attempt to make a recording of the lecture period if possible. I will make another discussion post sometime next weekend (the first lecture is next Friday) to report how it went.
Update 2: Report here.