@imbckagn: i think you are using any plugin or something else, because in Google normal search you won't get any description in site links and second only 8 site links are allowed by Google (in normal and original search).
Looks like this is another one of the many, many tests Google is always running. I can see why they might want to test something like this layout for a navigational search - rather than stretching out many separate results from the same domain the way they currently do so often.
In addition to having 12 sitelinks, another significant part of this is that there are snippets for each one. This is something that was reported here in early March [webmasterworld.com]
that will get people hopping over to Bing
I'm not so sure about that. For example, if someone enters only a domain name in the search box, I can see that they might appreciate direct links into various parts of that site. At least I can see why Google would want to test the idea.