A machine with one of the longest ball times is Lord of the Rings which makes it fun to play for kids.
Since it is based on a children's story it should be fine for kids as well. Lots of people have seen the movies and a lot of the original sound bites are in there, making it attractive.
Also there is so much to do in that game that it will stay fun for adults for a long time as well.
The only disadvantage is it had lots of toys which means lots of things can break potentially. Stop by the specific thread to see if that is doable for you.