This document discusses sustainable computing and greening the data center. It notes that exponential growth cannot continue indefinitely on a finite planet. It then discusses how Sun Microsystems has achieved a 44% reduction in servers, 88% space compression, and a 3,227 metric ton reduction in CO2 emissions in their Santa Clara campus data center. Their European data center achieved a 50% utility reduction and 80% space compression. Top-down support is needed to implement sustainable changes. Virtualization technologies and cloud computing can help reduce costs and energy usage. Betfair achieved a 60% reduction in power and cooling for servers through sustainable technologies. Sun's flexible work program has 14,803 participants, saved over 6,600 seats equaling $63.