Microsoft's Gen4 data center architecture involves trucks pulling up to an open air park and plugging right in to the Internet. No roof. Looks a little like an electrical utility transformer station.

Check out the video.

<a href="http://video.msn.com/?mkt=en-US&playlist=videoByUuids:uuids:b4d189d3-19bd-42b3-85d7-6ca46d97fe40&from=msnvideo" target="_new" title="Microsoft Generation 4.0 Data Center Vision">Video: Microsoft Generation 4.0 Data Center Vision</a>