One of the most thoughtful, touching surprises that anyone can receive is something which relates to their childhood. For a complete surprise that the person turning 40 won't be expecting, arrange a surprise party at their favourite childhood location, or a place which meant a lot to them growing up. Whether it's on a beach, at a family holiday destination, or somewhere even more unique, nothing will come as more of a surprise than a party with all the friends and family at a location which used to mean so much. This is guaranteed to leave them feeling loved, important and very, very special!