In the fantasy novels of Rick Cook, a magic spell (in the old tradition) that made a night (from sunset to sunrise) appear to stretch to twice its normal length. It was created by a great wizard, Oblius, for his wedding night, but turned out to be of little use to him, as (as Bal-Simba put it) "his reach exceeded his grasp." The spell proved, however, to be of tremendous use to the programming team working on refinements to WIZ-DOS, as programmers often work at night anyway.

The spell worked by creating an area in which, to someone inside it, time appeared to pass half as quickly. Seen from the outside, people in that area would be moving twice as fast. It was possible for someone outside the area of effect to enter, though with some resistance.

Source: Rick Cook, The Wizardry Compiled (spell also used in The Wizardry Cursed)