Hi,
Sandwich generation This term is used to refer to people who are simultaneously faced with the responsibility of caring for their young children and their aged parents. They are sandwiched between these two generations, the one before them and the one after them. It's recognized as one of the many sources of stress in modern life.
Club sandwich generation This is a relatively new variant of the above term. It refers to those people who have to care not only for their parents and their children, but also for their grand-children. Modern life is getting complex, isn't it? The humour, of course, lies in the reference to the multiple layers that make up a club sandwich.
Best wishes, Clive