Cognition is a new open source product similar in spirit to Trails. Both are approaches using Tapestry and Hibernate to streamline the process of creating a "typical" web application. Trails is very domain driven, creating the database schema from the object model. Cognition includes graphical editors inside Eclipse to build the schema, and derives the object model from the schema. There's a really impressive viewlet showing how to create a simple app really, really fast.
I can't wait for some time to open up in my schedule so I can give Rails, Trails and Cognition a spin.