If your goal is to get a JSON object out of .NET using $.getJSON so you can 1) wire up event handlers to the arrival of your JSON and 2) maybe even cache it on the client side for multiple pages to use, check out http://sex-death-and.com/blog/devign-werks/json-serialization/ -- it wires up a couple of classes for JSON serialization, runs them through an .aspx that does the serialization, downloads the data to the client via $.getJSON and then triggers events based on the data.
Hope it helps.
