People putting on plays including grand shocks (8)
I believe the answer is:
staggers
'shocks' is the definition.
'people putting on plays including grand' is the wordplay.
'people putting on plays' becomes 'stagers' (people staging plays).
'including' means one lot of letters goes inside another.
'grand' becomes 'g' (synonyms).
'stagers' placed around 'g' is 'STAGGERS'.
(Other definitions for staggers that I've seen before include "Reels about like gagsters" , "rolls" , "Disease on farm" , "is astonishing" , "causes amazement" .)