I don’t know about others… but I hate learning a language/framework in isolation from a project. Writing an insipid tutorial project that I don’t care about doesn’t involve me, and so I don’t learn as well. Also, the applications written alongside tutorials tend to be very carefully chosen to hit all the good parts of a framework, while ignoring the rough spots. Thus I’ve historically viewed “prototyping my next project” as a great time to pick up something new.
So. I started Rails tutorials on Friday, didn’t touch it at all over the weekend, and by mid-morning on Monday I had my proof-of-concept app. I’m storing legal documents described in XML, allowing people to fill in some defined fields on them, then generating custom PDFs/RTFs/PNGs/whatevers using Apache FOP. (That sounds more complex than it is. I’ll post an example later.)
Rails itself is being reasonably unobtrusive, which I approve of. I had to do minor research into how to set up custom mime types for response formats, but it turned out to be quite simple.