Well, check out wattOS:
wattOS is designed to be a "Green OS". wattOS is a Ubuntu-based desktop Linux distribution aiming at running computers in a lightweight but fully-featured way using less energy. wattOS is also targeted to run on older recycled computers.
wattOS WebSite: http://www.planetwatt.com/ [4]
Download the Beta 3.0 torrent in VDI format:
http://www.mininova.org/tor/2770189 [5]
Links:
[1] http://linux.philosweb.com/drupal/category/it/innovation
[2] http://linux.philosweb.com/drupal/category/it/open-source-foss
[3] http://linux.philosweb.com/drupal/category/it/softwareoslinux
[4] http://www.planetwatt.com/
[5] http://www.mininova.org/tor/2770189