महाभारत - कर्ण - अपातकानि पंच अनृतानि

विवाहकाले रतिसंप्रयोगे
    प्राणात्यये सर्वधनापहारे ।
विप्रस्य चार्थे ह्यनृतं वदेत
    पंचानृतान्याहुरपातकानि ॥

- महाभारत, कर्ण

vivAhakAle rati samprayoge
     prAnAtyaye sarva dhana apahAre।
viprasya cha arthe hi anRutam vadeta
    panchAni anRutAni AhuH apAtakAni ॥

- mahAbhArata, karNa

There are five instances when uttering a lie does not attract sin - during a wedding (to make it happen), romantic banter, when one's life is threatened, when you have lost all money and to help a (poor) brahmin.

- Mahabharata, Karna

[translator's note: http://wordsofwisdom.in/subhashitani/2010/07/28/]