Okay, this is a little silly. I like to whistle and I know Siri exists, but I'd love to be able to control my phone by whistling. Just a simple app that turns whistling sequences into arbitrary commands would be lovely. I've always thought it'd be good in combination with a flashcard app so that while driving I could whistle for the next flashcard (generally an audio flashcard when I'm doing language learning, for example), and whistle to indicate whether I got the answer correct or not.

So I was wondering what else I could use whistling for, and I thought it might be fun as a morse code teaching tool - you hear a letter or word and you have to whistle out the morse code for it.