Be forewarned that for some kids, Angry Birds can be both addictive and frustration-tantrum-inducing. DD9 is mature enough to find it fun and to put it down easily. DS5, who's also been more of a screen-oriented kid, gets screechy over it. I just uninstalled it from my phone, as a matter of fact.

There are some fun, relaxing kids' doodle apps out there. Tons of letter/number/reading ones. The Toca franchise is well loved.