Last year, the Earth Day drum started pounding early in the season, largely because it was the event's 40th anniversary.

The fever may have subsided a bit, but just about every company we've spoken to still had big plans on the agenda for Earth Day 2011.

To get a sense of how companies are celebrating the day, week or month, we turned to members of the GreenBiz Executive Network, along with some of our partners and friends, to see how the 41st Earth Day would play out on corporate campuses and in office buildings around the country.

Here's what they told us:

Kevin Anton, Chief Sustainability Officer, Alcoa

In celebration of Earth Day, World Environment Day and Arbor Day, thousands of Alcoa employees worldwide will volunteer to reduce their carbon footprint, recycle to save energy and plant trees to replenish the environment from April 21 to June 21, as part of Alcoa Foundation’s Green Works initiative. Alcoa Foundation will also launch the "Imagine Your World" art contest for children of Alcoa’s 59,000 employees, who will create original artwork depicting their vision for tomorrow’s natural environment. Eight young winners will each receive a U.S. $5,000 grant to their local school or a school in an underserved area.

Beth Colleton, Vice President, Green is Universal, NBC Universal

As part of our companywide Green is Universal initiative we have year-long efforts to recognize and celebrate sustainability both internally and externally, which extend to almost every part of our business. We launched Earth Week, our eigth green-themed week this past Sunday, which is one of two times a year that all the properties of NBCUniversal come together to inform and entertain our audiences around the environment. Internally, we have more than 14 environmentally-focused events happening in the U.S and globally.

Cynthia Curtis, Vice President & Chief Sustainability Officer, CA Technologies

(We'll) organize volunteer events globally, host sustainability days at some of our major locations, and we’re also announcing a newly established Green Star Award.

Holly Emerson, Senior Analyst, Center for Energy Efficiency and Sustainability Climate Solutions Sector, Ingersoll Rand Company

We are coordinating and encouraging all sites across the world to host an Earth Day activity for employees. Activities include electronics recycling, Bloom Challenge (we all plant bulbs), dumpster dive, bike to work, nature walk, eating local lunch and learn, clean the highway, gas cap check, bike donations (Trips for Kids).

Amy Hargroves, Manager, Corporate Responsibility, Sprint

We are having a large Earth Day event on our campus where we invite internal and external groups to have booths, display green vehicles, give away tree kits, live music, food, etc. It is one of our biggest events each year with 1,000 or more attendees. We’ve had Earth Day events for at least five years. This year, we’re expanding the effort to have much smaller events at an additional 14 sites. We’re also expanding some of our environmental employee-oriented programs -- green parking, better fitness center benefits for our employees who use their bicycle to get to campus. We’re also having a contest where employees register for our online Smart Commute program and get entered for a drawing to win two Vespa scooters. Smart Commute helps employees find car pool partners, allows them to track alternative transport for work, find out about mass transit and more.

Michael Kobori, Vice-President, Social and Environmental Sustainability, Levi Strauss & Co.

We’re launching a pilot program this Earth Day at our San Francisco headquarters that builds sustainability into the way we handle sample garments and fabrics. As part of our sample garments recycling program, we’re installing donation bins to collect wearable apparel accumulated during the design process. The wearable donations will be sold or distributed to the people in our community who need it most. We have a long-standing relationship with the San Francisco Goodwill and have partnered together again on this project to make the bins available year-round at our headquarters.

Eric Olson, Senior Vice President of Advisory Services, BSR

Earth Day is primarily serving as a milestone which internal sustainability champions can use to both help drive the pace and raise internal and external visibility of their sustainability efforts. In an interesting way, Earth Day also provides an opportunity to test new concepts and related messaging around "green" with less fear of "greenwash" than at other times. There is greater acceptance -- even an expectation -- that companies will talk about their environmental efforts on or around Earth Day.