An
irresistable urge to
snack, often brought on by a
big fat doobsker or three.
To observe the munchies in action, simply stake out the crisps and/or biscuits area of a 24 hour garage in any university town.
Patronising and Obvious Translation for Colonials:
...stake out the chips and/or cookies aisle of a 7-11 in any college town.