。
She had a great time at the concert.
Literal
She [topic-は] concert [at-で] enjoyably spent.
音楽会 is a slightly formal-flavored word for 'concert,' often used for classical or recital-style performances; for pop concerts コンサート is more typical, and for live rock or indie shows ライブ is the everyday word. 楽しく過ごす ('to spend [time] enjoyably') is a versatile fixed collocation: 連休を楽しく過ごす, 子供時代を楽しく過ごす — anywhere a span of time can be enjoyed.