I implemented these examples in Ruby 1.9, would love to know if there are more efficient ways of doing some of these:

    def cook(p1, p2, f)
      puts "get the " + p1.to_s
      f.call(p1)
      f.call(p2)
    end

    cook( "lobster", "water", lambda {|x| puts "pot " + x })
    cook( "chicken", "coconut", lambda {|x| puts "boom " + x })

    @a = [1,2,3]
    @a.map {|x| puts x*2}
    @a.map {|x| puts x}

    def sum(a)
      @a.reduce(0) do |a, b|
        a + b
      end
    end

    def join(a)
      @a.reduce("") do |a, b|
        a.to_s + b.to_s
      end
    end

    puts "sum " + sum(@a).to_s
    puts "join " + join(@a)