For us pagans, it's the return of Eostar (the original springtime goddess the later festival was named after). Easter bunny is a corruption of our magical March animal, the hare - bunny rabbits were not native to the British Isles but a late introduction by the Romans, so our Celtic religion celebrated the hares as a symbol of Eostar.
Anyone who's been out in the fields this time of year and seen the hares boxing will know why our ancestors thought they were oddly humanoid!
For druids, it's called Alban Eilir and for most pagans probably just 'the Spring Equinox'.
Here's some basic info about the Equinox:
http://www.druidry.org/obod/festivals/eilir.html
I sometimes do a ritual, sometimes not. But always go out and about walking, and gardening and feeling the spring come back to the earth in as real a way as I can.