keep-everything-alive/Assets/Plugins/RandomIEnumerables/RandomIEnumerables.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

// From https://stackoverflow.com/a/2019433/
public static class RandomIEnumerables
{
    public static T PickRandom<T>(this IEnumerable<T> source)
    {
        return source.PickRandom(1).Single();
    }

    public static IEnumerable<T> PickRandom<T>(this IEnumerable<T> source, int count)
    {
        return source.Shuffle().Take(count);
    }

    public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source)
    {
        return source.OrderBy(x => Guid.NewGuid());
    }
}