This labor resulted in a side adventure or parergon: On his way to the chase, Heracles was entertained by the centaur Pholus, who set before him a jar of wine that belonged to all the centaurs in common.
-- P. O. Morford, Robert J. Lenardon, Classical mythology
"It is a singular thing that you at the outset of your career - even as I thirty years ago at the same point of mine - should take up such a parergon and alight upon the same discovery."
-- Stanley John Weyman, Chippinge
Parergon consists of a combination of Greek roots, para- meaning "beyond, and ergo meaning "work, labor."