Creating a Contact using the API

Creating a Contact using the API

What is the minimal JSON required to create a contact using the API? I am passing in samples I find on the web and on the API site but I only get 
  2. {
  3.   "code": 2,
  4.   "message": "The request passed is not valid."
  5. }
which is worthless. Doesn't tell me what is wrong and how I can fix it. 

Thanks
Ralph