Start from anywhere, 99bottles of beer song.

99_bottles.rb

# 99 bottles of beer on the wall 
# get a number of bottles
puts 'How many bottles do you have?'
bottles = gets.chomp.to_i

# set the loop to go til there are no more bottles
# we should be able to do this as an ".each do ||" 
# but ruby has the hate today.
while bottles != 0
  # get the song going
  puts "#{bottles} bottles of beer on the wall."
  puts "#{bottles} bottles of beer!"
  puts 'Take one down, pass it around.'
  puts "#{bottles - 1} bottles of beer on the wall!"
  # can drop the subtraction in at then end of the loop section
  # -= is nice shorthand that doesnt require brackets or anything
  bottles -= 1
end

puts 'AND THEN WE ALL DRANK WHISKEY!!!'