Debian GNU/Linux is the operating system of the server.
Apache is the web server.
Python is the language used by all scripts, either the pages served by apache and the offline scripts used to parse mails received by the observer. It's the first time I'm really happy with a language I'm using.
modpython is a module for apache to speed up the execution of python scripts, so the interpreter isn't loaded for each hit and imported modules are kept in memory.
MySQL is the database server used to store the status of all games, the histories, the information about the logins, ...