Proc#=== allows you to do this:

  def multiple_of( n )
    lambda{ |x| x.modulo( n ).zero? }
  end

  case 10
  when multiple_of( 3 ):
    puts "3!"
  when multiple_of( 4 ):
    puts "4!"
  when multiple_of( 2 ):
    puts "2!"
  end

Basically you can now run code when checking case equality (===).

Since we're talking Ruby 1.9 here, that code won't even run :-( .. drop the colons and you're good though! :-) But if we're really talking Ruby 1.9, you could also go with:

    ->(x){ x % n == 0 }

Or, more simply:

    case $stdin.gets.chomp
    when lambda {|matchobj| matchobj.count("!") > 1 }
      puts "Quitcher yelling!"
    when "hi"
      puts "Hi yourself"
    end