Wordnet 3.0
NOUN (2)
1. 
 a game in which prizes (e.g., candies or coins) are concealed in a container and for a small sum a player can draw one out at random; 
2. 
 a selection or decision purely at random; 
- Example: "their system of hiring people seemed to be a sort of lucky dip"
WordNet (r) 3.0 (2006):
lucky dip
    n 1: a game in which prizes (e.g., candies or coins) are
         concealed in a container and for a small sum a player can
         draw one out at random
    2: a selection or decision purely at random; "their system of
       hiring people seemed to be a sort of lucky dip"