still ugly, but I like it better

fizz.rb

#!/usr/bin/env ruby

(1..100).each do |n|
  out = ""
  if n.modulo(3) == 0
    out += "Fizz"
  end
  if n.modulo(5) == 0
    out += "Buzz"
  end
  if out == ""
    out = n.to_s
  end
  puts out
end