You could do a gathering at city hall or the county building and do an education program and open mic for people to share their beliefs. Personally, I like to share the good things atheist do or have done because I think a lot of folks believe only religious people can do good things.

I will wear my Agnostic.com T-shirt. I will not be seeking the company of other nonbelievers, as I am not part of any organised group, being one of the few nonbelievers in this part of the world. If anyone comments on the logo on my T-shirt, I will explain to them about this site, and who knows, I might discover that there are actually other agnostics or atheists around after all!

...I’d suggest forming Cascadia and declaring your freedom from religion! ...though, when the subduction quake happens ..yur gonna want our help ~

Definitely, need a bumper sticker! This is extra nice for me, as that is my birthday, so as long as I can remember my own birthday...I will have this day down, ?

Is this just a reason to party?

Awesome !

The blood orgy will be at the Howard Johnson on Route 8, immediately followed by a complementary breakfast serving succulent human babies.

Nice to try something, but good luck on herding cats.
Bring food, food always attract people XD

Go to evolvingfish.com
I think they help with souvenir and small fun stuff for an event. Or at least you can get ideas

Have me do something chess related. (rationality) chrischess.

Do nothing. Believe in nothing. You don't need to celebrate. Holidays are for believers

Community service event show one doesn't have be spiritual help others and atheism would support helping others now because now is all we have.

You can crucify the pope.

On second thought, that would give atheists a bad name. Don't do it.

The Xians are gonna have a brain aneurism over this if it gets enough coverage. You need a parade to really get people's attention in the press. Sort of like a pride parade but for atheism. A bunch of godless heathens going down Main St. USA denying the existence of god.

That's not gonna get ugly fast.

How about a visit to the local natural history museum?

Bake a cake shaped like a baby.