The Augean Stables - not to be confused with the Aegean Islands - were owned by a king named Augeus who possessed a huge cattle stable in the region of Elis in the Peloponnese which had never been cleaned during its many years of use. Putting it right became one of the 12 Labors of Hercules, task number five to be specific, who was given a single day and night to clean them out. It was expected to be an unpleasant task for the hero, but since he'd grown up with not one but two stepfathers renowned for wisdom - including one of my faves, King Radamanthes of Crete - Hercules simply rerouted two rivers to do the job. Augeus felt cheated, but the job was done.
More on the Augean Stables:
About.com Ancient History - Hercules' Labors