Standing in a room full of lined faces, Alan Yellowitz held up an orange drum shaped like a wineglass. "This one's called a djembe," he said. "It's from Ghana."

The 30 or so people watching him had, combined, amassed hundreds of years of living, although their recollection of those years was fading. Many stared off blankly, perhaps unable to remember what Ghana is. But one 85-year-old woman started tapping her hand on her thigh.

"Give it a try," Yellowitz said, quickly placing a 90-cm-high drum beside her and handing her a mallet.