Working with JSON when passing data back and forth to a server is usually a joy - except when it comes to dates. Try passing a 'datetime' field from C# through JSON and you'll end up with a field that looks like:
var date = new Date(parseInt(jsonDate.substr(6)));
The substr function takes out the "/Date(" part, and the parseInt function gets the integer and ignores the ")/" at the end. The resulting number is passed into the Date constructor. Note that we are NOT using 'eval' to parse the date.