Pony is a little project I started a year ago for quickly and simply sending mail from Ruby. The project showed a lot of promise, and many people were excited about it (as you can tell by the 30+ forks on Github); but I never found the time to take it to its full fruition.
So I’ve handed the reins over to Ben Prew of Vera Street Consulting. He’s already merged some great patches, including file attachments by Hiroshi Saito, now available in the 0.4 release on Gemcutter. And there’s even a Pony mailing list.