What is it called when Google displays several of your pages (indented) at the...

[jjdubya]

...top of the SERPs? and how do you get it to happen?

example: notice how nytimes has several links at the top of the organic serps
http://www.google.com/search?q=nytimes.com&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

[Lukene]

Google ranks pages, not web sites. Every page is a search entity that can reach the search engine page.
The indented display is for humans so they will notice the second page as part of the same site.
It is a UI (user interface) concept. I do not know if this UI has a specific name