random bookings.rb

require 'date'

def generate_date do
  now = Date.today().to_datetime()
  weeks_from_now = Random.rand(8)
  day_random = RandomGaussian.new(0.5, 0.25).rand()
  day_of_week = (day_random*7+1.5).round() % 7
  time_random = RandomGaussian.new(0.5, 0.1).rand()
  time = ((time_random*48+12).round() % 48)/2

  now + weeks_from_now.weeks + day_of_week.days + time.hours
end

class RandomGaussian
  def initialize(mean = 0.0, sd = 1.0, rng = lambda { Kernel.rand })
    @mean, @sd, @rng = mean, sd, rng
    @compute_next_pair = false
  end

  def rand
    if (@compute_next_pair = !@compute_next_pair)
      # Compute a pair of random values with normal distribution.
      # See http://en.wikipedia.org/wiki/Box-Muller_transform
      theta = 2 * Math::PI * @rng.call
      scale = @sd * Math.sqrt(-2 * Math.log(1 - @rng.call))
      @g1 = @mean + scale * Math.sin(theta)
      @g0 = @mean + scale * Math.cos(theta)
    else
      @g1
    end
  end
end