Every year Britain's Queen Elizabeth II invites some of her subjects to a garden party at Buckingham Palace. The invitations are extended to people who have accomplished something significant or deserve recognition for having served the country. A lucky few even get to have a conversation with her.

"Her Majesty requests ... " is how the invitation begins.

A more exclusive social event - at least in the UK - could hardly be imagined. There are three garden parties every year, usually in July.