There are several threads on similar topics, and many mudcatters already sing to people in nursing/retirement homes, so I'm sure you'll get plenty of good advice.Perhaps you could write down a list of songs you do know, and let your audience select from that. If you're likely to be singing on a regular basis then you can ask for songs they would like you to sing in the future - mudcat is a wonderful resource for finding seemingly 'lost' lyrics. The best of luck, whatever you decide to do. Don't forget to ask your audience to sing along!