Now that Rails 2.0 has been baked to near-perfection, I'm sure all you Rubyists with Rails applications are considering updating or have already updated your applications to be Rails 2.0-compatible. And you've probably already pored through the massive list of new features and changes in Rails 2.0 or seen it on Ryan Daigle's Scraps. Ryan also wrote a Rails2 mini eBook that's been getting good reviews.
I've been keeping track of the Rails Trac timeline myself since my 1st committed Rails patch mostly to keep track of Rails development (we run several apps on edge) and to monitor any comments on my submitted patches. Turns out keeping an eye on the timeline and the rubyonrails-core mailing list gives you a pretty decent "on the ground" view of new features and changes to the Rails trunk.
So I'm gonna try something and see if helps anyone: I'll be running a near-daily series of blog posts about new Rails features or changes. I'll try not to repeat anything that's already been mentioned, and instead focus more on lesser-known changes. I think it's also a great opportunity to raise the profile of the core committers and contributors to the Rails community so look out for an "About the contributor" section in each post.
Hop on over to the 1st post - Time#advance now uses :weeks, :hours, :minutes, :seconds options.