I participate in as many as I can!

My family is getting donations in their honor to charities this year. I am very excited to be able to provide presents for children in need. (I think this is a good thing to do each year, even if the organization near you may be 'religious'. It's for the kids!)

The Bridge for Youth has tons of bags filled with supplies coming their way from me as well, and I'm supporting the Santa run, though I won't be running.
Watch the Meet Up sites as well, we have charitable events such as highway clean ups and blood drives. I know I'm working on organizing a blood drive for the Southern Minnesota Atheists Meet Up Group right now.