Tinybop's newest app for kids is called Skyscrapers.
Discover how people build, live, and play in skyscrapers. Construct a skyline full of buildings! Go up and down, through every floor, and underground. Spark a blackout, fix a pipe, or clog the toilets. Test your building's engineering when dinosaurs invade, lightning strikes, or the earth quakes. Find out what keeps skyscrapers standing tall and people happy in them all.
I believe my kids have all of the Tinybop apps and love them...I'm downloading this one right now. See also a bunch of great educational-ish iPad apps for kids.