In which bars have swingers who score? (5,8)
I believe the answer is:
table football
'in which bars' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'swingers who score?' is the wordplay.
'swingers who' becomes 'table' (I can't justify this - if you can you should give a lot more credence to this answer).
'score?' becomes 'football' (football score is a kind of score).
'table'+'football'='TABLE FOOTBALL'
'have' acts as a link.
(Other definitions for table football that I've seen before include "Game with revolving soccer players!" , "Indoor game" , "Game played with model players attached to metal rods aiming to score goals" .)