Volunteering, IMO, should be a life-long pursuit. Everyone has their passions and interests. Volunteer for a cause that you believe in and because you sincerely want to help and benefit others. The last reason on the planet to ever volunteer for any charity or group, is because you can put it on your resume.
Even i you only have 1 day a month or a few hours a month, every sincere effort helps and is appreciated. You'd be amazed at how many hour we waste in a week when we could be helping others.
So whether it's homeless animals, children, Vets, the elderly, cleaning up beaches and parks, removing graffiti, the Special Olympics, working at a museum, working at a soup kitchen, or whatever......do a search in your area and try some different organizations out until you find one that works for, that you enjoy and feel you can be of value to and want to affiliate with. And for everyone..............you can even involve your family, friends, and neighbors. That way, you really are not taking much time away from your family, if that is a concern for some. And it will be a great, lifelong lesson/role model for your children that they can also carry on throughout their lives.