Bike to work, car pool, use mass transit, or walk.
Encourage your company to sign up for the Green Lights and Energy Star energy-saving programs offered by the U.S. Environmental Protection Agency. Contact EnergyStar at 888.STAR.YES (888.782.7937).
Assemble a team of co-workers to conduct an energy audit at your workplace. Look for lights and equipment needlessly left on, drafty windows and doors you could insulate, inefficient thermostat settings, and other energy-wasters. Make recommendations for improvements that will save energy and money.
Get a recycling or composting program started with the help of Keep America Beautiful. There are lots of ideas and resources at their Recyling@Work portal.
Put up an Earth Day bulletin board during April that offers employees new energy-saving tips each week.