def shuffle s
  samohlasky = 'aeioulr'
    shuffled = ""
    last = 'a'
    s = s.downcase
    s.length.times { |i|
      pos = rand*s.length
      it = 0
      while (s[pos,1] == '*') || (samohlasky.include?(last) == samohlasky.include?(s[pos,1]))
        pos = rand*s.length
        it += 1
        break if it > 100 && s[pos, 1] != '*'
      end
      shuffled << s[pos,1]
      last = s[pos,1]
      s[pos] = '*'
    }
    shuffled
  end


p %w{Use Pastie in your quest to save humanity, not in your evil plots to take over the world!}.
  collect { |word| shuffle word }.join(" ")
​



outputs something like:

"seu sitape ni yruo qetus to save taniyum,h ton ni yruo veli tlsop to take vreo teh drwo!l"