Ages and sexes (and any possible interests) would help people narrow it down. There's a geography quiz type of game here in our game section that was released today.
Depends on the age of your kids. I had a hard time to find somthing for my daughter who is less than 4 years old.
As I didn't want any in-App-Purchases or Ad-filled games, I am also willing to pay for good ones.
So in case your kids are young, check out "Camping" by Nana Games at Google Playstore or Amazon Appstore.
Same game for iOS has the name "Crayon Camping Advanture" on Apples AppStore.
Enjoy (and have fun watching your kids play).
Will
PS: Also very neat are the games of the company "Wonderkind".
PPS: Here come the links to the Android-Store-Sites for the above mentioned game: