Twilight is tolerable. The setup is quite good, but wasted (vampire politics are glossed over in favor of Bella's heartbeat). If you want to see what can be done with it go read Alicorn's Luminosity (discussion thread) which starts out a decent pamphlet for luminosity, then drops it and turns into a good book. (As in, not by the standards of online fanfic. By the standards of books.)
Twilight itself is just your usual crappy romance novel. It finds a few emotional buttons (danger, lust, beauty, resisting attraction, the high of infatuation) and presses them like a monkey on crack. It's quite possible to enjoy that. Secondary characters, while rather flat, are appealing - for example Carlisle Cullen's virtues can be genuinely moving.
I say grab it if you have time to waste, if the first five minutes bore you drop it, otherwise finish it.
Recent brainstorming sessions at SIAI (with participants including Anna, Carl, Jasen, Divia, Will, Amy Willey, and Andrew Critch) have started to produce lists of rationality skills that we could potentially try to teach (at Rationality Boot Camp, at Less Wrong meetups, or similar venues). We've also been trying to break those skills down to the 5-second level (step 2) and come up with ideas for exercises that might teach them (step 3) although we haven't actually composed those exercises yet (step 4, where the actual work takes place).
The bulk of this post will mainly go into the comments, which I'll try to keep to the following format: A top-level comment is a major or minor skill to teach; upvote this comment if you think this skill should get priority in teaching. Sub-level comments describe 5-second subskills that go into this skill, and then third-level comments are ideas for exercises which could potentially train that 5-second skill. If anyone actually went to the work of composing a specific exercise people could run through, that would go to the fourth-level of commenting, I guess. For some major practicable arts with a known standard learning format like "Improv" or "Acting", I'll put the exercise at the top and guesses at which skills it might teach below. (And any plain old replies can go at any level.)
I probably won't be able to get to all of what we brainstormed today, so here's a PNG of the Freemind map that I generated during our session.