I bought the Ruby on Rails Hors Serie 33 from Linux Magazine.
Not bad! I learned a lot from the different tutorial. I spent a few evening trying a few things out.
I found there were a few interesting things in Rails. I am not really in love with ruby though. This might only be because I felt a little annoyed of a few idiosyncracies of the language, I might get used to them though (in particular this global, not global variable thing).
There was nothing really problematic when you know enough of python, perl, java and the like.
What I really like though was: Rails. I tried it and you really get a few simple things done in very little time. That's really cool. I tried the address book example from the Hors Serie and I also implemented a little blog management system just for the heck of it.
I liked the ActiveRecord, and Action Pack and also the scaffolding stuff as well as the possibility to test it quickly with a small server.
