Ejemplos del uso de DateTimeOffset

DateTimeOffsetExample.cs

static class DateTimeOffsetExample
{
    static void Main(string[] args)
    {
        DateTimeOffset localDateTime = DateTimeOffset.Now; // Setting up a DateTimeOffset with my local machine time: 2012-08-07 05:50:00 pm Offset -05:00 (We are in DST)
        Console.WriteLine(localDateTime.DateTime); // Is a DateTime, the output is the time as was recorded in the client machine (no offset involved): 2012-08-07 05:50:00 pm
        Console.WriteLine(localDateTime.Offset); // A TimeSpan (hh:mm): -05:00:00
        Console.WriteLine(localDateTime.LocalDateTime); // A DateTime, because I'm on the same machine it is: 2012-08-07 05:50:00 pm

        //I'm creating this particular DateTime Offset for demostration, lets imagine I got this from the DB (for the record the client machine was on Bs As)
        DateTimeOffset buenosAiresDateTime = DateTimeOffset.Now.ToOffset(new TimeSpan(-3, 0, 0));

        Console.WriteLine(buenosAiresDateTime.DateTime); // Output: 2012-08-07 07:50:00 pm
        Console.WriteLine(buenosAiresDateTime.Offset); // Output: -03:00:00
        Console.WriteLine(buenosAiresDateTime.LocalDateTime); // Output: 2012-08-07 05:50:00 pm

        //Doing it by hand. We don't need to do this on .NET but this code will be similar in other platforms
        DateTime myDBTime = buenosAiresDateTime.DateTime; // I have Bs As datetime here on a simple DateTime object.
        TimeSpan offset = new TimeSpan(-3, 0, 0); // I also have the offset of that time. (-3:00)
        TimeSpan myLocalOffset = new TimeSpan(-5, 0, 0); // My local offset. (-5:00)
        DateTime UtcTime = myDBTime.Add(-offset); // First Step getting UTC, we just need to remove the offset to get it. (please notice the minus)
        DateTime myLocalTime = UtcTime.Add(myLocalOffset); // Adding my client computer offset to UTC so I get my local DateTime.
        Console.WriteLine(myDBTime); // Output: 2012-08-07 07:50:00 pm
        Console.WriteLine(UtcTime); // Output: 2012-08-07 10:50:00 pm
        Console.WriteLine(myLocalTime); // Output: 2012-08-07 05:50:00 pm
    }
}

Código extraido del mail explicativo de @jfazzini