I've recently convinced my management that our outdated version of Rails is slowing us down enough to warrant an upgrade. The approach we're taking is to start a fresh project with current technology rather than a painful upgrade. Our requirements for the project have changed and this will be much easier.

The biggest problem is actually that my knowledge of Rails is out of date. I've dealt only with Rails 1.2.4 while the rest of the world has moved on long ago. What topics have I missed by being buried in my work instead of keeping up with the current Rails fashion?

I'm hesitant to dig through blogs at random because I'm not sure how much has changed between the intervening versions of Rails. It's no use to learn Rails 2.1-2.3 specific stuff that is no longer useful for Rails 3.