Randomize a List<T>

Here's another instalment in a sporadic series of useful C# extension methods. This time we return a List in a random order:

public static class ICollectionExtensions
{
    /// <summary>
    /// Randomizes the specified source.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="source">The source.</param>
    /// <returns></returns>
    public static ICollection<T> Randomize(this ICollection<T> source)
    {
        Random rng = new Random();

        T[] a = new T[source.Count];
        source.CopyTo(a, 0);

        byte[] b = new byte[a.Length];
        rng.NextBytes(b);

        Array.Sort(b, a);

        return new List<T>(a);
    }
}