Have you tried "Go Tell Aunt Rhody?"

I've done similar things, in a small way. In high school my sister and I took friends to hospitals to have sing-alongs in some of the wards. My sister took her accordion, or someone from the Red Cross wheeled a piano from room to room! We took requests, both of us could play stuff like "Camptown Races" by ear and we were surprised at the amount of participation.

Lately I've played for the geriatrics unit of a mental health facility. It was very good for the patients. Old folks who usually fall asleep during the activities were singing, requesting songs and even dancing a little. Doing this makes me happy and I want to do more. It's good for my confidence, too! These aren't critical audiences. They just want to have fun.