{
"2010": [
    {
        "type": "vacation",
        "alloc": "90.00"
    },

{
"year": [],
"2010": [
    {
        "type": "vacation",
        "alloc": "0.00"
    },

static void Main(string[] args) {

var json = @"
{
  '2010': [
  {
    'type': 'vacation',
    'alloc': '90.00'
  },
  {
    'type': 'something',
    'alloc': '80.00'
  }
]}";


var jss = new JavaScriptSerializer();
var obj = jss.Deserialize<dynamic>(json);

Console.WriteLine(obj["2010"][0]["type"]);

Console.Read();

}