Happy Earth Day.

Everyone is invited to the party.

The celebration is happening all over Major League Baseball -- and we even found a three-ounce bag of Yankees Grass Seed at the MLB.com Shop just in case you want to display the very same Kentucky Bluegrass mixture that the groundskeepers just planted in the new Yankee Stadium.

It is happening in Pittsburgh, where Alan Hershkowitz throws out the ceremonial first pitch before the Pirates' 12:35 p.m. ET energy-free game today against the Marlins. He is a senior scientist for the Natural Resources Defense Council, which partnered with the Pirates last year to launch the team's industry-leading Let's Go Green program -- and energy-free means every dollar spent on electricity at the ballpark will be matched with a dollar spent on natural energy resource development.

"Earth Day is the perfect opportunity for the Pirates to highlight the many programs we have implemented that are making tangible positive contributions to the greening of our environment," Pirates chairman Bob Nutting said. "As I said when we launched our Let's Go Green campaign last year, we did not decide to do this because it is popular; we did it because it was the right thing to do. We are very pleased with the program's success in the first year and that we were able to enhance it this season."

It is happening in Anaheim, where the Angels actually started celebrating Tuesday night at their Green Day game against Detroit. Fans received an Angels banner made of recycled materials; vendors showcased environmentally responsible products and services, including Subarus in front of the Home Plate Gate; fans who brought any recycled item received free gifts like Angels tickets, movie passes, coupons and other sponsor-donated items. Green Team volunteers walked through aisles during the sixth and eighth innings to collect bottles and cans for recycling.

"Besides putting a winning team on the field, Angels Baseball is also committed to having a winning team off the field," Angels president Dennis Kuhl said. "And that means making a commitment to our community by promoting environmentally safe practices within the family-friendly setting of Angel Stadium. For the last couple of years we have been working closely with our facility personnel, food service and merchandising partners to utilize environmentally friendly products and services throughout the ballpark. Green Day is one more way the Angels can promote greater awareness and support for the standards of environmental stewardship."

It is happening in ballparks everywhere, and it also is happening right now at the MLB.com Shop. Here are 10 examples of how you can celebrate Earth Day by ordering items there that can reduce your own carbon footprint and in some cases simply show even more love to the surface we play the games on:

1. Great American Reds Aluminum Water Bottle: These 34-ounce bottles are eco-friendly and free of BPAs (industrial chemicals).

2. Mariners Duncan Recycled Adjustable Cap: These are 51-percent cotton, 49-percent polyester (recycled plastic bottles). Each cap contains approximately two 20-ounce bottles. When you wear it, it's just a cap.

3. Team Sports America White Sox Solar Lantern: Finished in a look of antique copper with a stained-glass effect, this comes a rechargeable NI-CD battery that can be replaced and an LED bulb that is rated to last 100,000 hours -- equivalent to 11 years.

4. Astros Toddler Organic Cotton T-shirt: This shirt from Soft as a Grape is 100-percent organic cotton, and even has an organic fan screen print. Whatever the team logo, it is a good way to be green early in life. Want to get them started even earlier? Get a Braves Infant Organic Cotton Creeper.

5. Forever Collectibles Mets Work Gloves: Spring means working around the yard for many, and you might want to use these gloves to fill that Mets Ceramic Planter.

6. Red Sox Women's Organic Crochet Tank Top: This is from Alyssa Milano's TOUCH collection, and it's 100-percent organic cotton with the team logo on the hip. Women also might like the Phillies Organic Fan T-shirt or Dodgers Missy Organic V-Neck T-shirt.

7. Forever Collectibles Dodgers Gnome Garden Stone: Proof that fans can have a green thumb and still think blue. As with so many items in the MLB.com Shop, this is available in other club logo treatment as well.

8. Team Sports America Cardinals Home Plate Stepping Stone: Be the first on your block to add one of these 12-inch-wide stones to your landscaping. There also is a version that looks a lot more like an actual stone, and you can use it as a wall plaque as well.

9. Highland Mint Brewers Gold and Infield Dirt 3-Coin Set: The coin in the middle of this beautiful cherry-wood box says: "Authenticated Infield Dirt." Or their rival fans might be looking at the Wrigley Field Infield Dirt Photo Mint. If you don't think that matters to fans, then you don't know baseball fans. Let 100 of us down on the warning track, and most are definitely planning to scoop up some dirt to put into a pocket.

10. Memory Company Athletics Art Glass Coaster Set: Coasters protect your wood. You buy less wood. Of course, you also can just keep drinking out of that Great American Athletics Aluminum Water Bottle.

Or just go out to a Major League Baseball game, and participate in the industry-wide greening of the game. The celebration is happening in Washington, where they have an Earth Day ticket promotion for fans who ride the Metro to the night game against Atlanta. All fans who present their Metro farecard or SmarTrip card at the Nationals Park box offices will receive $3 off any ticket priced at $10 or more.

Nationals Park is the only LEED-certified outdoor sports arena in the country. The park has a 6,300 square-foot green roof over the left-field concession stand, high efficiency field lights, recycling bins throughout all concourse, more than 250 bike racks and a bike valet program which operates out of Parking Lot C.

Meanwhile, it is time to watch Hershkowitz throw out the first pitch in Pittsburgh, and it is time to appreciate the fact that the Pirates recycled more than three-quarters of a million bottles and can in 2008. The breakdown was: 2.95 tons of aluminum cans, 16.77 tons of plastic, 193 tons of cardboard and catalogs, 870 pounds of glass, and 20,100 gallons of used cooking oil.

Ride your bike to the Pirates' game today and you get $5 off any ticket of $12 or more.

Earth Day is every day, but especially today. The celebration goes on, complete with real ballpark grass seed for the occasion.