One of my best friends came to visit me this afternoon while I was on Kiddo-duty (my mom was teaching piano lessons). She brought her two little boys, ages 4 and 2. The 4 year old found the jack-in-the-box in the closet, brought it out, and loved it. His brother quickly caught on to the fun, and the two of them loved startling themselves with the "POP!" each song. Kiddo of course needed to see what was going on, and figured out it was lots of fun. The three of them laughed and giggled through each song for at least 5 minutes (an eternity in little kid time).
This wouldn't be worth noting if she didn't have her own jack-in-the-box at home that scares her enough that it stays in the closet far out of sight. Will she like hers when she gets home? It's not clear.