Wondering about a specific technique Options

[fuzzywumpit]

I'm wondering how a certain technique is created, or at least what it's referred to so I can research it. I'd like to know how to create a page where the content is centered in its own "pane" in the center of the page, with a different background behind it.

It can be seen here:
http://www.wysiwygwebbuilder.com/index.html
http://xkcd.com/
http://explosm.net/

[Darin McGrew]

Here's one technique:
http://www.alistapart.com/articles/customcorners/

[pandy]

Different backgrounds for different blocks. A simple case, one background for BODY, then center a DIV of a certain width, put all your content in that DIV and use another background image or color for it. You can go on forever if you want.