This function converts a Google Maps V3 (Javascript API) of MVCArray of lats and longs (MVCArray<LatLng>) to Well Known Text (WKT). The result will be something like POLYGON((50 0, 0 20, 10 10, 50 0))

gistfile1.js

function MVCToWKT(arr){
  var result = 'POLYGON(';
  for(ring = 0; ring < arr.length; ring++) {
    var strRing = '(';
    for(i = 0; i < arr.getAt(ring).length; i++) {
      strRing += (i > 0 ? ", " : "") + arr.getAt(ring).getAt(i).lng() + ' ' + arr.getAt(ring).getAt(i).lat();
    }
    //Add the first point to the end to close polygon
    strRing += ', '+arr.getAt(ring).getAt(0).lng() + ' ' + arr.getAt(ring).getAt(0).lat();
    strRing += ')';
    result += (ring > 0 ? ", " : "")+strRing;
  }
  result += ')';
  return result;
}

I made this function because I couldn't find an easy way to convert a Google polygon to the WKT format in order to use it to save it to MySQL.