Diyis is a project mainly written in RUBY and JAVASCRIPT, it's free.
DIYIS for Rails3 and Ruby1.9.2
DIYIS: Do-it-yourself Interactive Stories.
This is the repository for the project at diyis.org, the intention of which is to allow users to create interactive stories. These are expanded versions of Choose Your Own Adventure books, allowing simple state manipulation, interpolation and other enhancements to the basic scheme.