RewriteEngine On
Options +FollowSymLinks

### THIS IS A LITTLE EXTRA SECURITY AND CAN BE REMOVED

RewriteRule ^includes/(.*) index.php
RewriteRule ^vb/(.*) index.php
RewriteRule ^packages/(.*) index.php

### THIS IS THE ACTUAL REWRITE

RewriteRule ^threads/([0-9]+)(?:/?$|(?:-[^/]+))(?:/?$|(?:/page([0-9]+)?)) showthread.php?t=$1&page=$2&%{QUERY_STRING}
RewriteRule ^members/([0-9]+) member.php?u=$1&%{QUERY_STRING}
RewriteRule ^forums/([0-9]+)(?:/?$|(?:-[^/]+))(?:/?$|(?:/page([0-9]+)?)) forumdisplay.php?f=$1&page=$2&%{QUERY_STRING}
RewriteRule ^blogs/([0-9]+)(?:/?$|(?:-[^/]+))(?:/?$|(?:/page([0-9]+)?)) blog.php?u=$1&page=$2&%{QUERY_STRING}
RewriteRule ^entries/([0-9]+)(?:/?$|(?:-[^/]+))(?:/?$|(?:/page([0-9]+)?)) entry.php?b=$1&page=$2&%{QUERY_STRING}
RewriteRule ^list/([^/]*/)([0-9]+) list.php?r=$1$2&%{QUERY_STRING}
RewriteRule ^content/(.*) content.php?r=$1&%{QUERY_STRING}
RewriteRule ^widget/config/([0-9]+) widget.php?r=config/$1&%{QUERY_STRING}

https://www.vbulletin.com/forum/forum/vbulletin-4/vbulletin-4-questions-problems-and-troubleshooting/333733-mod-rewrite-friendly-urls-htaccess