In an effort to reduce energy usage and increase efficiency for the purpose of helping the environment, various governments (not limited to the USA) are pushing for the adoption of new "compact fluorescent bulbs" as a suitable replacement for their standard incandescent types.
The US Government sponsored program, named "Take the Pledge," aims to increase awareness of the bulbs and encourage replacement. They maintain a number of registered participants, with the estimated number of pounds of CO2 that they've helped to prevent. Other governments, including that of Australia, Canada and the UK, are planning to completely replace the bulbs shortly after the year 2010.