The story has come to be called "The Widow's Mite" and can be found in Luke 21:1-4. Jesus is watching people give their tithes in the temple. While many rich folks come along and pour in piles of money, a widow comes by and puts in two tiny coins. Jesus praises her for true sacrificial giving and notes that the rich are just giving from their leftovers.
Above is a picture of what the "mite" or lepton looked like.
