Some bridge down — stare at it? (10)
I believe the answer is:
rubberneck
'stare at it?' is the definition.
(rubberneck can mean to stare at something)
'some bridge down' is the wordplay.
'some bridge' becomes 'rubber' (rubber bridge is a variety of the card game bridge).
'down' becomes 'neck' (both can mean to finish a drink).
'rubber'+'neck'='RUBBERNECK'
(Other definitions for rubberneck that I've seen before include "attribute useful to contortionist" , "Turn one's head to stare foolishly" , "Slow to see accident" , "Gawper" .)