My COSI 7HRL entry
An erg (short for ergon, a Greek word meaning "work/task") is a unit of energy and mechanical work equal to 10^−7 joules. It originated in the centimetre–gram–second (CGS) system of units, symbol "erg". It is not an SI unit. (...) An erg is approximately the amount of work done (or energy consumed) by one common house fly performing one "push up", the leg-bending dip that brings its mouth to the surface on which it stands and back up.
Wikipedia contributors. "Erg." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 27 Feb. 2015. Web. 5 Apr. 2015.