From SITUATIONIST INTERNATIONAL ANTHOLOGY
(Guy Debord, 1956):
Theory of the Dérive
Among the various situationist methods is the dérive [literally: 'drifting'], a technique of transient passage through varied ambiances. The dérive entails playful-constructive behavior and awareness of psychogeographical* effects; which completely distinguishes it from the classical notions of the journey and the stroll.
In a dérive one or more persons during a certain period drop their usual motives for movement and action, their relations, their work and leisure activities, and let themselves be drawn by the attractions of the terrain and the encounters they find there. The element of chance is less determinant than one might think: from the dérive point of view cities have a psychogeographical relief, with constant currents, fixed points and vortexes which strongly discourage entry into or exit from certain zones.
*Psychogeography was defined in 1955 by Guy Debord as the "the study of the precise laws and specific effects of the geographical environment, consciously organized or not, on the emotions and behavior of individuals."Another definition is "a whole toy box full of playful, inventive strategies for exploring cities...just about anything that takes pedestrians off their predictable paths and jolts them into a new awareness of the urban landscape."The most important of these strategies is the dérive. (Wikipedia)