At first, kids are bored by perfectly fine musical entertainment (7)
I believe the answer is:
karaoke
'musical entertainment' is the definition.
(I've seen this before)
'at first kids are bored by perfectly fine' is the wordplay.
'at' is a charade indicator (letters next to each other).
'first kids' becomes 'k' (1st letter of 'kids').
'bored by' is an insertion indicator (to bore something can mean to drill into it).
'perfectly fine' becomes 'a-ok' (I've seen this in another clue).
'are' placed around 'aok' is 'araoke'.
'k' put next to 'araoke' is 'KARAOKE'.
(Other definitions for karaoke that I've seen before include "Musical entertainment, offered in bars and clubs" , "It's Japanese for 'empty orchestra'" , "Singing to pre-recorded tune" , "Singing to background recording" , "Often cringeworthy and drunken singing to a video tape" .)