Merb is an MVC framework that is ORM-agnostic, JavaScript library agnostic,
and template language agnostic, preferring plugins that add in support for
a particular feature rather than trying to produce a monolithic library
with everything in the core. In fact, this is a guiding principle of the
project, which has led to third-party support for
the ActiveRecord, DataMapper, and Sequel ORMs. 

WWW:    http://www.merbivore.com/
WWW:    http://rubyforge.org/projects/merb/