Passing dynamic json object to C# MVC controller

I am doing some work with .Net 4, MVC 3 and jQuery v1.5

I have a JSON object that can change depending on which page is calling it. I'd like to pass the object to a controller.

{ id: 1, title: "Some text", category: "test" }

I understand that if I create a custom model such as

[Serializable]
public class myObject
{
    public int id { get; set; }
    public string title { get; set; }
    public string category { get; set; }
}

and use this in my controller such as

public void DoSomething(myObject data)
{
    // do something
}

and pass the object using jQuery's .ajax method like this:

$.ajax({ 
    type: "POST", 
    url: "/controller/method", 
    myjsonobject,  
    dataType: "json", 
    traditional: true
});

This works fine, my JSON object is mapped to my C# object. What I'd like to do is pass through a JSON object that's likely to change. When it changes I don't want to have to add items to my C# model each time the JSON object changes.

Is this actually possible? I tried mapping objects to a Dictionary but the value of data would just end up being null.

Thanks