doctor.rb

queue = []

gargling = Thread.new do
  loop do
    queue << "It's time to gargle"
    sleep 60 * 60
  end
end

pills = Thread.new do
  loop do
    queue << "It's time to take pills"
    sleep 60 * 60 * 3
  end
end

alarm = Thread.new do
  loop do
    if msg = queue.shift
      system %{ say "#{msg}" }
    end
    
    sleep 1
  end
end

[alarm, gargling, pills].each &:join