We are in the process of experimenting with Radiant CMS at work, and while looking at the sites that have been built with it, I stumbled across an excellent (and aparently well loved) Ruby site called Try Ruby (in your browser).
I’m sure im the last person in the world to have visited this site – but in case im not, go check it out. For beginner ROR’s like myself, it offers a really nice inline tutorial interface, and for advanced ROR’s… well im sure you know what you can do better than me!!