Essential Types C# Book

Format string Meaning
o Round-trippable
r, R RFC 1123 standard
s Sortable; ISO 8601
u "Universal" Sortable
U UTC
using System;
using System.Text;
using System.Globalization;
class Sample
{
public static void Main()
{
DateTime dt = new DateTime(2000, 1, 2, 17, 18, 19);
Console.WriteLine("{0:U}", dt);
}
}
The output:
Monday, January 03, 2000 1:18:19 AM