What kind of charity do you volunteer your time to? Do you do it for a reason or in memory of someone, if so what is that reason?

Spring has gotten me thinking about all the charities I would spend my time volunteering for. This is the time for all the walks, runs, bike rides for this cause or that cause. I used to work for a company that did alot of volunteering and I was the treasurer for the board of our market, this was in addition to my regular job. But in doing so I did alot of volunteering to were each year I would get the presidential award for volunteering at least a certain number of hours http://www.presidentialserviceawards.gov/tg/pvsainfo/dspAboutAwards.cfm

I would love to hear what charities you volunteer for, the kind of things make you volunteer your time and if you do it for a particular reason or because you lost a loved one.