Interesting comparison of Ruby on Rails and J2EE. Author shows that J2EE application may be quite similar to RoR application (well, if you use Struts and Hibernate instead pure Servlets & EJB :). But code base of Ruby app is much more simpler and cleaner, and there is no XML configuration files!
Good news for C# lovers is that MonoRail project provides something similar (with Ajax support!). Promising, but I don’t like the idea to use NVelocity instead ASPX engine – component model works better for me.