Spectacles in time slipped into Bill Gates's trousers? (8)
I believe the answer is:
pageants
'spectacles' is the definition.
(I've seen this before)
'time slipped into bill gates's trousers?' is the wordplay.
'time' becomes 'age' (an age is a period of time).
'slipped into' means one lot of letters goes inside another.
'bill gates's trousers?' becomes 'pants' (US term for trousers - eg for Bill Gates).
'age' put inside 'pants' is 'PAGEANTS'.
'in' is the link.
(Other definitions for pageants that I've seen before include "ceremonial events" , "Dramatic or spectacular tableaux" , "Rich and spectacular ceremonies" , "spectacles" , "Elaborate processions or tableaux" .)