This is an interesting one. ActionMailer classes don't reload. That is, if I make a change in such a class, I have to restart webrick for changes to take effect. And I'm in the development mode... It seems that there is a ticket for this. Here's the URL: http://dev.rubyonrails.org/ticket/1262, but as you can see it was closed 2 years ago!
I'm running Ubuntu and using the packaged version of Rails (1.2.1).
Anybody know how to fix this?