Entertainment, having taken to bed (5)
I believe the answer is:
futon
'bed' is the definition.
(type of bed)
'entertainment having taken to' is the wordplay.
'entertainment' becomes 'fun' (fun is something entertaining).
'having taken' indicates putting letters inside.
'fun' enclosing 'to' is 'FUTON'.
(Other definitions for futon that I've seen before include "Mattress used as a bed or sofa" , "'Japanese mattress, can be folded (5)'" , "Japanese mattress with frame, a bed-couch" , "Kind of Japanese bed convertible to couch" , "Type of sofa bed" .)