Oh Appy Day! gives you the scoop on the coolest apps from some of the coolest people anywhere. This week, author Gretchen Rubin shares her fave.

I try not to make a habit of handing my iPhone to my six-year-old, but one app, Pocket Piano, has proved very handy during emergency bouts of impatience and boredom. My daughter loves to tap away at the little piano keys, and to record and listen to herself tapping away. Even just changing the pattern of the keyboard keeps her absorbed. – Gretchen

Oh Appy Day!

Download the Pocket Piano app for your Apple gadgets at iTunes.com

Gretchen Rubin is the author of the best-selling The Happiness Project. Learn more about Gretchen’s refreshing perspective on happiness at Happiness-Project.com or follow her on Twitter @GretchenRubin where she’s always got something cool to say.