Note everyone having a good time (4)
I believe the answer is:
ball
'a good time' is the definition.
(I've seen this in another clue)
'note everyone' is the wordplay.
'note' becomes 'b' (musical note).
'everyone' becomes 'all' (all people).
'b'+'all'='BALL'
'having' is the link.
(Other definitions for ball that I've seen before include "Sphere for sport" , "Sphere - dance" , "Spherical object" , "Orb" , "Squash, say" .)