This is a very invasive request and should be laughed at and denied. A small joke about posting that on Glassdoor.com might even be appropriate. (Glassdoor.com lets you post company and even interview experiences, it is very handy for researching prospective employers.)

The best practice would probably be to inform them that you keep your professional and private life separate, and direct them to your public website or linkedin profile . If they persist, it really tells you something about the HR department and company environment.