It's a busy time of year for celebrations: If you're Jewish, there's Passover; for Christians, it's Easter; and Pagans, well, that's where Earth Day comes in, we suppose. Unless you already have plans to worship Gaia by the light of the moon, consider chowing down for a cause today. For every person who drops in to L'Artusi or dell'anima, the restaurants will plant a tree in conjunction with the American Reforestation Project. Meanwhile, across the river in Williamsburg, Cadaques Tapas Bar is offering a $35 ecoconscious vegetarian prix fixe this evening, served by candlelight. And if you'll be stocking up for Pasqua at Eataly, look for the lineup of sustainable purveyors handing out samples, including Acme Smoked Fish and Salvatore Brooklyn. Each shopper also gets a packet of arugula seeds (as do diners at other B&B restaurants). Because, you know, "Plant some arugula, man" has a nice 21st-century ring to it.