The Common Gateway Interface - in short: CGI - is the oldest and simplest way to create dynamically Webpages.
When we write a CGI script by ourselves, most time we use the Jim Tcl interpreter. IkiWiki uses Perl for its CGI scripts.
Since CGI has some disadvantages with respect to performance, improved technologies like FastCGI have been developed.
Yet another different way to create dynamic web pages is to integrate a script interpreter into the webserver, our prominent example for this is PHP.
Our trouble ticket system ‘roundup’ uses Python.
See Script Interpreters for references to the mentioned languages.