Some simple clouds made according to a blender cookie tutorial using Nick Keeline's cloud generator add-on.
I suggest you check those two points : 1/ You may be running a version of blender that doesn't match the file ( it was made with version 2.57 apparently, so you need to have blender 2.57 or more recent) 2 / Maybe you need to install / activate the addon that is mentioned in the description of the file ? see here : http://www.blendernation.com/2010/04/16/cloud-generator-script-for-blender-2-5/
When i opened it there was nothing and I couldn't look around????????????? :(