My "IsPalindrome" solution

        static bool IsPalindrome(string s)
        {
            if (s == null)
                throw new NullReferenceException(); // if we don't get a string throw exception

            // Remove all commas, spaces and so on (except letters) and switch to lowcase.
            // For cases like "Never, Odd Or Even."
            s = Regex.Replace(s, "[^a-zA-Z]", "").ToLower();

            if (s == "")
                return true; // or "false". Really I don't know if empty string Palindrome or not. So it is depended on our agreements

            var arr = s.ToCharArray();
            return arr.SequenceEqual(arr.Reverse());
        }

        static void Check(string s, bool shouldBePalindrome)
        {
            Console.WriteLine(IsPalindrome(s) == shouldBePalindrome ? "pass" : "FAIL");
        }

        static void Main()
        {
            //Check(null, false);
            Check("", false);
            Check("abcba", true);
            Check("abcde", false);
            Check("Mr owl ate my metal worm", true);
            Check("Never, Odd Or Even.", true);
            Check("Never Even Or Odd", false);

            Console.ReadLine();
        }