Validanguage is an object-oriented, unobtrusive JavaScript form validation library that does not rely on any JavaScript frameworks (optional Prototype integration).

It provides 2 APIs:

• HTML-like API placed inside comment tags. The choice for ease of use and simplicity.
• JSON-based API for advanced configuration.

With Validanguage, you can:

• use the pre-configured functions like required, minlength, maxlength, etc.
• easily configure custom validation functions to be triggered at onblur, onsubmit, onchange events.
• add onsuccess and onerror callback functions to integrate it into your existing site design.
• & more..

P.S. Thanks to Dan for the suggestion.

It is a time consuming process to create an admin interface with standard functions such as add-edit-delete-update again and again.

ActiveScaffold, a Ruby On Rails plugin handles all the ActiveRecords smartly. It adds add-edit-delete-update functionality with an Ajaxed interface & sorting, searching and pagination support.

ActiveScaffold features:

• AJAXified table interface for creating, updating, and deleting objects
• Automatic handling of ActiveRecord associations
• Sorting, Search and Pagination
• Graceful JavaScript degradation
• RESTful API support (XML/YAML/JSON)
• Sexy CSS styling and theming support
• More extension points than you can shake a stick at
• Guaranteed to work on Firefox 1+, IE 6+ and Safari 2+
• Released under the MIT License, the same one as Rails itself, so you can use it freely in your commercial applications.