Swine gets a good deal, hosting a Scottish celebration (8)
I believe the answer is:
hogmanay
'scottish celebration' is the definition.
(I know that Hogmanay is a type of scottish celebration)
'swine gets a good deal hosting a' is the wordplay.
'swine' becomes 'hog' (hog is a kind of swine).
'gets' means one lot of letters go next to another.
'a good deal' becomes 'many'.
'hosting' means one lot of letters goes inside another (inserted letters are welcomed in or hosted).
'many' going around 'a' is 'manay'.
'hog'+'manay'='HOGMANAY'
(Other definitions for hogmanay that I've seen before include "Scottish New Year's Eve" , "Annual celebration" , "New Year's Eve in Glasgow" , "New Year's Eve (Scots)" , "New Year up north" .)