Heard is a useful app for settling those "but *I* said and then *you* said" arguments with your kids.
When you activate the app, it begins recording everything around you on a 12-second buffer (extend it to five minutes for $1.99). Any time you want, click the “Push to save” button to save the current clip. Do nothing, and the self-destructing buffer lets the audio slip into the ether.
Why would anyone not in the NSA want an app like this? With Heard, you can capture anything from your baby’s first words to a key point in a lecture without hovering your thumb over the record button all day.