holy grail

Short definition from Wiktionary

Noun

1. 1
   Alternative letter-case form of Holy Grail.
2. 2
   Anything that is highly sought-after but attained only through difficult endeavor.

Proper noun

1. 1
   An artifact in Arthurian mythology, being the cup used by Christ at the Last Supper and in which some of his blood was caught during the crucifixion.
2. 2
   A web page layout with fixed-width columns to the left and right, and a central area that fills the remaining space.