Volunteering

I want to give back.....but how do I do that? I work outside and inside the home full time. I've got 2 children under 7. My husband and I run a business (in addition to my full time career). I'm supposed to be exercising and can't find the time (although some may argue I should be doing that rather than this).

I would really like to find something where I could volunteer say 1 evening a week/month (after the children have gone to bed) close to home. Is that too little/too late? Does anybody have any ideas?

Where do you volunteer?