Here are the best open source scripts that are top rated by users.They are categorized into different category as CMS(Content management system) or called as portals,Blogs,ecommerce,groupware,forums,elearning,image galleries,wiki and many more.
We have produced the 3 top ranked listing in each category.You can see more in http://www.solidscripts.com or http://www.opensourcecms.com/.
Content Management System (CMS)
Drupal is software that allows an individual or a community of users to easily publish, manage and organize a great variety of content on a website. Tens of thousands of people and organizations have used Drupal to set up scores of different kinds of web sites. Drupal is open source software licensed under the GPL, and is maintained and developed by a community of thousands of users and developers.