If you count church stuff, then yes. I teach religious ed on Saturday mornings to two nine year olds. I used to be a literacy volunteer in my early 40's. I liked doing that but it's really not such an easy thing keeping a student motivated.
My son Jay told me he is doing some soon. He joined a group that mentors young low-income kids. If the kids join the group they can earn money for college. It is a state-sponsored thing but the workers are all volunteers. He loves working with kids and says that being a soccer coach doesn't give him enough to do to help the boys.