Team reveals secondary activities (9)
I believe the answer is:
sideshows
'secondary activities' is the definition.
(a sideshow is a secondary show)
'team reveals' is the wordplay.
'team' becomes 'side' (both can mean a sports team).
'reveals' becomes 'shows' ('show' can be a synonym of 'reveal').
'side'+'shows'='SIDESHOWS'
(Other definitions for sideshows that I've seen before include "Entertainments" , "fairground attractions" .)