My kids are 5 and 2 now. We've done stuff mostly through the church to tell the truth, but when we lived in TX I was involved in a homeless shelter and a couple friends and I would go hang out with the kids, bring oranges or some yummy healthy treats, and visit with the kids. My 2 friends who are good at the drama stuff would do a puppet show me and another friend had the "job" of sitting on the floor and getting hung on. We'd have to spread our legs straight out so that we could fit more children. 2 on my lap, 2 on my legs, 2 hugging and holding onto my shoulders or neck, my arms holding hands or patting shoulders. Occasionally I'd bring my son to play with the children there (especially when I found some that I knew he'd like to play with). They'd just play and run and have fun, we'd have a snack time, we'd do the puppet show or tell a story, we'd pray with the kids and have some time where we'd practice lessons---how to apply what we learned. My older son saw the other children. It wasn't a "scary" place, it was clean. But he knew that they were living there and not in a house, and that wasn't too good. He had a little understanding that not everyone has a house and a million toys and books in the playroom. This helped him be more WILLING to share, to take better care of things because he saw in real life that they are luxuries and not just "automatically there". We'd do little events at the shelter where some ladies in our church were professional hair stylists and they would give free haircuts, and I'd be in charge of a nice dinner and some basic classes like how to fill out an application, or assistance with a resume, interviewing skills, some basic life skills like banking or whatever, others would donate business attire for going job hunting in, some kids would donate the toys and play with the children, we'd have music and a church service, etc. For other things that were not child appropriate (another shelter on the "bad" side of town, etc) I wouldn't let my son see that or go there, but we would line bags up at the church in aisles and he was only 2 at the time and would walk up and down the aisles with me. We'd drop one winter cap in each bag, then 1 pair of gloves, 1 bag of small toiletries, 1 bag condiments/cutlery (because we were feeding them later and just easier to have the bags packed with everything they needed and then they move on to the cafeteria style dinner), etc, etc. We went to Children's hospital and had a fun production with dancing, costumed people, games, face painting, etc. I did face painting and my son went with my bff to pull the wagon and pass out gifts to the children who were able to come down.
Now: we've gone to the nursing home where my friends again did the free haircuts and I would paint fingernails and my son would give them little giftbags with treats, candy canes, toiletries, flameless candles, non-slip fuzzy socks or slippers, small gifts that the nursing home suggested for us to bring, and he would just be cute and try to talk to them a bit. He can now call out the things for the Bingo game ( "B-5" ) or help use the dobbers to mark them because some people have trouble hitting it or finding it fast enough.
There's a boy in one of his little classes right now that is having a really bad time this year. The mom is single and has been without work for a bit, she has 2 little kids (ages 5 and 8) that live with her---the 8 year old found out the cancer came back. Her adult daughter's kidney is failing. Her adult son got in a fight with his gf and they were arrested and the 8 month old child taken away, now living with her......all in a little apartment. We adopted them and bought each child 3 new wrapped gifts, plus gave her some baby stuff my youngest has outgrown but we hadn't donated yet (an umbrella stroller, portable crib, high chair, christmas tree and ornaments, etc). An angel tree from a hospital, foster care place, capa, wherever---they're all over the place! The boys have both been on mission trips (just here in the states for now), on Indian reserves where we've helped set up a classroom and a clinic, distributed clothing and supplies, etc. My 2 year old doesn't really know much, but he is seeing from an early age that a lot of children don't live in a house like ours or have powerwheels to ride on or whatever. It will all be contextual later as he gets a little older and can put it together. Joseph has seen videos from the church some of the neat things that are being done in some other countries and expressed a desire to go there and help.
If you look in your local community's paper, I'm sure there will be plenty of information on opportunities there. Info on angel trees, military stuff, toys for tots, different events, food banks, foster/adoption agencies needing help organizing, Be a Santa to a Senior, book clubs that distribute books to children, the library may also be a resource for opportunities in your area (the resource desk). There are some opportunities that may be a lot of fun if done in the right spirit. Good luck!