K.R.
You could volunteer somewhere - soup kitchen, homeless shelter, animal shelter, transitional living centers, holding babies in the NICU, assisted living for the elderly, local public elementary school (doesn't have to be the ones your kids are at), meals on wheels, local churches would probably have lists of places that need volunteers.
Volunteer work doesn't always have to be people oriented if you aren't comfortable with meeting strangers. I worked at a transitional living center for women for a while and they always needed volunteers to help with gardening and upkeep of the grounds, or painting in the building, or someone to fix the basketball hoop for the kids...
If you knit, there is an organization my cousin has been knitting baby hats for for babies in third world countries. My grandma was part of a sewing group and they made over a hundred Raggedy Ann dolls to donate to an orphanage once, as well as other donated blankets and soft sewn toys. I have a friend who enters contests like "win a month supply of cupcakes" and when she wins she takes them to the children's cancer treatment center where her daughter died seven years ago to cheer up the kids in treatment.
There are lots of opportunities out there, and lots of people who would appreciate you using your time for them.