As seen in: Indiana Jones And The Last Crusade

The Power: The Holy Grail is the cup, goblet or plate used by Jesus at the Last Supper. It is said to be imbued with all sorts of miraculous powers and, in fiction, the hero must prove and battle to be worthy in its presence.

The Real Life Version: The development and history of the Grail legend is a complex one, some experts arguing that it derived from Celtic myth while others believe it is a purely Christian symbol. While the Grail first came to prominence in a poem by Chretien de Troyes, it is Robert de Boron's verse romance Joseph d'Arimathie that introduced the idea of a Holy Grail with Joseph acquiring the chalice to collect Christ's blood upon the cross - Joseph later founded a line of guardians in Britain to keep it safe. The search for the grail also plays an important part in Arthurian legend, most famously revolving around the knight Sir Galahad. Conceptions of it vary, some texts describing variously as a bowl, a cup or a platter. It has even been described as a stone that fell from heaven.

Ownership of the Grail has been assigned to various groups, most famously the Knights Templar in the 12th and 13th Century. Differing sources ascribe the whereabouts of the Grail to different Churches, mostly in Spain.

The Movie Version: "The Holy Grail was sort of feeble," says Lucas. "But, at the same time, we put the father in there to cover for it. I mean, the whole reason it became a dad movie was because I was scared to hell that there wasn't enough power behind the Holy Grail to carry a movie." While the Grail is said to have mystical properties, the notion of it granting immortality is completely an invention of the filmmakers.

Effectiveness as a MacGuffin: 3/5 It's true that a cup doesn't overflow with cinematic possibilities but, nevertheless, the Grail legend sets up some intriguing backstory and the search for the Grail provides a nice metaphor for the journey of reconnecting father-son relationships.