// Example of a UNIX timestamp for 11-29-2013 4:58:30
double timestamp = 1385701110;
// Format our new DateTime object to start at the UNIX Epoch
System.DateTime dateTime = new System.DateTime(1970, 1, 1, 0, 0, 0, 0);
// Add the timestamp (number of seconds since the Epoch) to be converted
dateTime = dateTime.AddSeconds(timestamp);