gistfile1.rb

class Car
  attr_accessor :vin_number
end

my_car = Car.new
my_car.to_s => "Car#<79860879878>"

# to_s is already defined via Object.to_s. Since Car inherits from Object, we get it for free.
# We can also redefine it to make it more useful too:

class Car
  attr_accessor :vin_number

  def to_s
    vin_number
  end
end

my_car = Car.new
my_car.vin_number = "123asdf"
my_car.to_s => "123asdf"

# We can also use the "my_car" variable in a String and it will implicitly call "to_s":
puts "#{my_car}" => "123asdf"