Drink at ball game (9)
I believe the answer is:
hopscotch
'game' is the definition.
(hopscotch is a kind of game)
'drink at ball' is the wordplay.
'drink' becomes 'scotch' (Scotch is an example**).
'at' says to put letters next to each other (I've seen this in other clues).
'ball' becomes 'hop' (informal dance event).
'scotch' put after 'hop' is 'HOPSCOTCH'.
(Other definitions for hopscotch that I've seen before include "child's play" , "Children's game with squares on ground" , "kids jump about in it" , "minor diversion?" , "Traditional children's game" .)