National Volunteer Week starts today. (If you live in Santa Clara County, you might consider the volunteer possibilities listed now on the Santa Clara County Library website, including an adult literacy program.)
I've volunteered at various times at libraries, our daughter's schools, our church, and a homeowners association. The experiences have been pretty positive, all in all. I think volunteerism is some of the grease for society's wheels; without it, things might grind noisily to a halt.
I should also add, though, that you are the best judge of what you can give. Volunteering may not be for you, at least at this time. Knowing when to say "No" can be as important as knowing when to say "Yes." Be good to yourselves -- even as you take a moment to say thanks to a volunteer.