Roger Chartier is a musician / singer entertainer who has specialized in senior entertainment for a long time.
Having worked with many activity directors over the years, I have gleaned knowledge of what it takes to entertain a variety of levels of senior audiences as well as handicapped audiences of differing ilk's.
With guidance from many activity director friends, I am the author of several articles on the subject.
There are many non-musical entertainment activities, as well.
You will find some ideas here on the other pages of this website.
There are a lot of good ideas for Alzheimer's activities, Dementia activities, sing-a-longs.
As an example of what an entertainer can do check his web page: http://www.rogerchartier.com/seniors.html
You may be interested in this incredibly informative website. www.seniorsentertainer.com