Day's social gathering provides entertainment for tossers? (7)
I believe the answer is:
frisbee
'entertainment for tossers?' is the definition.
(you toss a frisbee in the air)
'day's social gathering' is the wordplay.
'day's' becomes 'fri's' (abbreviation for Friday).
'social gathering' becomes 'bee' (bee is a kind of social gathering).
'fris'+'bee'='FRISBEE'
'provides' acts as a link.
(Other definitions for frisbee that I've seen before include "Plastic disk for skimming through the air" , "One may be thrown" , "Light, plastic disc for throwing" , "Light, plastic disk for throwing" , "Thrown plastic disc-like toy" .)