I volunteer moderate two recycling/freecycling yahoo groups in my area, I volunteer in the baby room once a month at church, I volunteer once or twice a month as needed for registration and security at our Kid's church, I do the prep for the craft projects at home for the pre-school age classes at church, my husband is on the greeter's team and the mowing team at church, he helps elderly people or women with children load their car in the parking lot at the store, we've paid the bill for other people at a restaurant before - usually an elderly person or couple, or a military person, we have volunteered for a few years at local street festivals put on by the city in different capacities, and all the little niceties already mentioned by others like holding the door, making it a point to smile, say hi and compliment others, etc.
My husband and I try to teach our kids by example when it comes to volunteerism and as a result, my daughter has been doing a lot of volunteer work with the younger children at our church, she's done some volunteer work at the animal shelter, a horse therapy facility, a local senior center, and as a Junior Girl Scout she's done some work with a couple of younger Brownie troops mentoring, and teaching crafts.
There are so many ways we can give back to society and we try to do little things each day to make someone's day a little brighter and our world a better place.
Blessings,
N.