WebAPP is awesome, what more is there to say. A great open source, flat file system, perl based, web portal. And of course, open source means free, and always improving. It currently has all the features you mght need, from forums to articles, downloads to photo galleries, it even has a light version for handheld browsers. Because its a flat file system, that means no SQL database! It offers the freedom to change the theme, the language, and add any content, while remaining user friendly, very well designed. A very impressive package, and at the price they're asking (absolutely free!) likely your first choice for a pre-made web portal. Not convinced? Take a look at the demo offered at their homepage, you can see the potential.

WebAPP (Web Automated Perl Portal) system has been in development since 2002. It was originally based on the Poas (Perl on All Site) script, which was in turn originally a YaWPS (Yet Another Web Portal System) based script. WebAPP continues to add features, improve code, and strengthen security in the years since its development began. Current features include articles/news, forums, links section, downloads, polls, gallery, instant messaging, anonymous email, recommend us, send news article, statistics and visitor monitoring, light formatted page for handhelds, and many others.