Here is a list of php scripts for creating forum portal. They are responsive design, easy to edit and setup.
phpForum v1.5 – Social Forum Script
phpForum is an innovative web platform built with the help of php and mysql.
Tractor is a simple PHP and MySQL based internet forum.
Tickets Plugin: Articles + Forums
This plugin extends Tickets with an Articles (aka Knowledge Base) storage section.
Easy Forum Script
Easy forum is a ready script for forums. It’s easy to integrate and install in any website.
Simple Forum Module for CMS pro
Korum – Kohana-Based Forum
Korum is a simple yet clean forum board built with Kohana 3 PHP framework.
Forumium – Fully Responsive Forum Script
MoonLight Bootstrap Responsive Forum System