Pakyow: Knock out your hardest hitting projects. http://pakyow.com/
Ruby On Rails - Open source web development framework in Ruby http://rubyonrails.org/
Django - Makes building web apps easy. https://www.djangoproject.com/
Pyramid is a small, fast, down-to-earth Python web application development framework. http://docs.pylonsproject.org/projects/pyramid/1.0/