There are groups that visit housebound elderly people. Or at least, I know that several churches and nursing homes around me do that. Ask around, and I bet you'll be able to find people doing this! These groups are always looking for volunteers.
In my area, one such service is organised through the red cross. Everyone you visit has requested a visit, so I think it works out well. One might be able to work through them or, time allowing, start a local service doing similar.
