AudioSurf is a great game for a great community.
For my tiny nephews I once created a mobile game. Even at 2 years old they started using a tablet but there were no good games with educational value. Therefor I created SNAbaKEby, a game teaching children letters and how to put them together to a word. Since the game was appreciated by my family, I published it for Android. If anyone is looking for a mobile game for their young kids and feel content for letting them play with it while you got uninterrupted time to talk to other family members, here it is: https://play.google.com/store/apps/details?id=com.snabakeby.zoo_eng&hl=en