The Mars Society is switching their entire online presence to a Google Sites hosting and design solution. This very robust, powerful platform will offer extensive integration with Google Docs, easy maintenance, and long-term viability. Design tools are limited but evolving.
If you would like to help migrate the current site (MarsSociety.org) contact the Mars Society, here: http://www.marssociety.org/portal/author/MarsSocInfo
The above screenshot is from the Mars Desert Research Station's new (still beta) Google Site, here: https://sites.google.com/a/marssociety.org/mdrs/home