arr.rb

# Faster random records
module ActiveRecord
  class Base
    def self.random(limit = 1)
      if (total = count) > 0
        highest_possible_offset = [0, total - limit].max
        offset = [rand(total), highest_possible_offset].min
        num = [limit, total].min
        offset(offset).limit(num)
      else
        self
      end
    end
  end
end