Polish original and English translation: http://simple.wikipedia.org/wiki/Wlaz%C5%82_kotek_na_p%C5%82otek
Lojban translation by ianek:
lo mlatu cu bitmu cpare sei
ke melbi selsanga be fa dei
nalclatei naltortei prane se'u
i doi mlatu ko sanga za'ure'u
(would it sound awkward if there were {dei} in place of {ke}? I can't say — ianek)