I've been trying to decide on a new project to work on with Ruby on Rails, and I think I'd like to try my hand at a webmail application like Squirrelmail.
Of course, I'd more than likely have to implement an SMTP server to go along with it due to the fact that most SMTP servers don't work with Rails-friendly databases. Of course, if anybody knows of any that do, by all means let me know.
What I'm aiming for is a decent webmail, possibly eventually with functionality like Gmail has. I think every site should be able to offer webmail with that sort of functionality. Of course, that means I'll have to brush up on my Javascript. I'm going to host the project on Rubyforge, and I'll post a link once I get it approved so everybody can take a look at it.