3D grid type effect

I've seen a few wallpapers with 3D grids that twist and wave around and I was wondering how this is done.

I can make grids but it looks nowhere as near as cool :/

Thanks guys ;)

like this??
http://www.sidez.net/pixel/trendy.jpg

if that's the one you're looking for... its called pseudo wireframe

http://www.stridingstudio.com
there's a guide/tutorial there....

hope its the one you're looking for