I mostly give money to local charities, like the homeless shelter and the food bank. When it comes to other types of donations, though, I love Habitat for Humanity. I have worked on a few Habitat houses, and no matter how klutzy you are they can find something useful for you to do.
While giving money to worthy causes is a great thing to do, there's something very meaningful about doing actual work in a house where you know a family is going to live. And in every one of the houses I've worked on, the future homeowner has been there to help, and you get to meet the person you're helping. It's a great feeling. And, as an added bonus, I have learned how to do lots of stuff around my own house.
They provide all sorts of wonderful services to blind people, including one-on-one volunteers, which is what I do.
Although various lighthouse programs exist all over the country (the one in New York City is the best known), they are each independently operated.
romansperson - I’m not sure where you’re located, but if you are interested in personally volunteering with the blind, check and see if there is a lighthouse in your area. They usually need people both as one-on-one volunteers (reading, shopping, paying bills, etc.) for individuals, and to make tapes. In San Francisco we have people who read the newspaper onto a radio service every day. Your mother might also want to check to see if there are services available which could help make her more independent.
My favorite is Doctors Without Borders (Medicins sans frontieres–sp?), a group of medical professionals who travel the world giving medical assistance to those who desperately need it, like people in poor, remote or war-torn areas. They won a Nobel Prize in 1999.
I also give to the Cystic Fibrosis Foundation–my friend’s wife has the disease.
I give to the local chapters of the Cancer Society and the Girl Scouts, to my university and to my former employer, The Nature Conservancy.
If you’re unsure about giving to an environmental organization, you might feel more comfortable giving to TNC. They are essentially non-political, they have a very systematic and studied approach to land conservation, they work closely with local groups (land owners, governments, other environmental orgs) to protect open space and they’re very respectful of donors’ wishes.