I think of FRP as a Dream that's still being worked on.  So to get at the basics of the Dream I do a lot of gedankenexperiment, sketching on pen and paper, and code fragments.  I read Conal Elliott's blog to gather the results of his investigations of that Dream.

But I understand that you're a practical kind of guy and prefers to push and poke to learn stuff, and I think all the projects mentioned in this thread are excellent starting points.