Instant Rails is a one-stop Rails runtime solution containing Ruby, Rails, Apache, and MySQL, all preconfigured and ready to run. No installer, you simply drop it into the directory of your choice and run it. It does not modify your system environment.
RadRails is an integrated development environment for the Ruby on Rails framework. The goal of this project is to provide Rails developers with everything they need to develop, manage, test and deploy their applications. Features include source control, debugging, WEBrick servers, generator wizards, syntax highlighting, data tools and much much more.