Tomorrow, it's the NYC Parks Department's Eggstravganza 2005 in Central Park! While the activities are ostensibly for children, it seems like everyone can join in the fun, like the egg hunt, Easter egg dying, an Eggstacle, and a petting zoo (just don't put your fingers in your mouth after petting the animals). It doesn't seem like the Peeps Fun Bus is in town the way it was last year, but there will be Central Park's Biggest Cha Cha and Electric Egg Slide - woo!
Here's a PDF map of what's happening where and when in the park tomorrow. Gothamist Food on Easter culinary delights, and there's also Gothamist's recipe for Easter Fun Balls. Joe Schumacher has some great Peep-related links, like The Lord of the Peeps.
Photograph of Easter festivities in Central Park from rion.nu's Easter 2004 series