Active Directory keeps track of time in 100 NS intervals (UTC) since January 1st, 1601. Had to write this quick parsing method so I can work with AD exported data.

DateTime.parse_ad_format.rb

class DateTime
  def self.parse_ad_format(datetime)
    datetime  = datetime.to_i
    datetime /= 10_000_000      # Convert nanoseconds to seconds
    datetime -= 11_644_473_600  # Get the difference between 1600 and 1970
    strptime(datetime.to_s, '%s')
  end
end