Using the tools I know (HTML, CSS, JS) I've made a few "digital doodles":
On the other hand, if you're a real developer something cool to look into is Intel's XDK, a cross-platform development environment. One of the programmers I work with had it set up in Brackets (a free and wonderful code editor) and was able to write once, publish to multiple platforms and devices.
There's also the task of getting an app on the various marketplaces: iTunes Store, Google, etc.