Mahamrityunjaya Mantra:

Om Tryambakam Yajamahe
Sugandhim Pushtivardhanam
Urvarukamiva Bandhanan
Mrityor Mukshiya Maamritat

Literal meaning:

Tryambakam = the three-eyed one (accusative case)
Yajamahe = We worship, adore, honor, revere
Sugandhim = sweet fragrance (accusative case)
Pushti = A well-nourished condition, thriving, prosperous, full, and complete
Vardhanam = One who nourishes, strengthens, causes to increase (in health, wealth, well-being); who gladdens, exhilarates, and restores health; a good gardener
Urvarukam = disease, attachment, obstacles in life, and resulting depression (accusative case)
Iva = like, just as
Bandhanan = stem (of the gourd); but more generally, unhealthy attachment
Mrityor = From death
Mukshiya = Free us, liberate us
Ma = not
Amritat = Immortality, emancipation 

Usable meaning:

Om, We worship The Three-Eyed One (Lord Shiva)
Who Is Fragrant (Spiritual Essence)
And Who Nourishes All Beings
May He Severe Our Bondage Of Samsara (Worldly Life),
Like A Cucumber (severed From The Bondage Of Its Creeper)
And Thus Liberate Us From The Fear Of Death,
By Making Us Realize That We Are Never Separated From Our Immortal Nature 

Listen to a traditional version of the chant here.
Listen to it performed more as a song here.  This is the version I play in class.