One thing I've been thinking about would be posts specifically designed to elicit discussion, rather than teaching about something.
To give an example, someone on /r/LessWrong posted a question about creating a rationalist sport. It's fun and interesting to talk about and it's a good way of exercising things like "holding of on proposing solutions."
I suggested recently that part of the problem with with LW was a lock of discussion posts which was caused by people not thinking of much to post about.
When I ask myself "what might be a good topic for a post?", my mind goes blank, but surely not everything that's worth saying that's related to rationality has been said.
So, is there something at the back of your mind which might be interesting? A topic which got some discussion in an open thread that could be worth pursuing?
If you've found anything which helps you generate useable ideas, please comment about it-- or possibly write a post on the subject.