Nice example there TCS of 'skinning.'
Our server is running unix. On top of that we run one of the premium brands of webserver software. Linked to that is the forum software, essentially a high speed sql database which is then skinned to produce the look and feel you witness here.
Many skins are available or you can simply roll your own if you have the time, skill and a good sense of design. We have always wished we had more time to impart on honing and developing a far more exclusive look to the site but server load goes up exponentially when we pile on the eyecandy.
Regards
rob