rake

namespace :pick do
  desc "Pick a random user as the winner"
  task :winner => :environment do
    puts "Winner: #{pick(User).name}"
  end

  desc "Pick a random product as the prize"
  task :prize => :environment do
    puts "Prize: #{pick(Product).name}"
  end
  
  desc "Pick a random prize and winner"
  task :all => [:prize, :winner]
  
  def pick(model_class)
    model_class.find(:first, :order => 'RAND()')
  end
end

In lib/task/something.rake

terminal:

rake pick:winner
rake pick:prize

rake -T