Ruby on Rails

Ruby on Rails is an open-source web framework that's optimized for programmer happiness and sustainable productivity. It lets you write beautiful code by favoring convention over configuration

What's in the package?

Rails is a full-stack framework for developing database-backed web applications according to the Model-View-Control pattern. From the Ajax in the view, to the request and response in the controller, to the domain model wrapping the database, Rails gives you a pure-Ruby development environment. To go live, all you need to add is a database and a web server.

Who is already on Rails?

Everyone from startups to non-profits to enterprise organizations are using Rails. Rails is all about infrastructure so it's a great fit for practically any type of web application Be it software for collaboration, community, e-commerce, content management, statistics, management, you name it. Examples:

Basecamp: Project management. The original Rails app by 37signals.	Campfire: Group chat for biz. Pushing the limits of Ajax in Rails.
43things: Achieve your goals in life.	ODEO: Record and share audio.
Shopify: E-commerce made easy.	Fluxiom: Digital asset management.
Strongspace: Secure file hosting.	Typo: Put your weblog on Rails.
See more applications

What else do I need?

Rails works with a wealth of web servers and databases. For web server, we recommend Apache or lighttpd, running either FastCGI or SCGI, or Mongrel. For database, you can use MySQL, PostgreSQL, SQLite, Oracle, SQL Server, DB2, or Firebird. Just about any operating system will do, but we recommend a 'nix-based one for deployment.

If you need hosting, TextDrive is the official Ruby on Rails host, offering fantastic plans with a knowledgeable staff. Whether you need shared or dedicated hosting, these guys are experts in Ruby on Rails. For alternatives, see the wiki for a full list of Rails web hosts.

from: http://www.rubyonrails.org