Songify is a music making app aimed at those who can't sing or play any instrument. Insead you simply talk into Songify for a while and it'll take what you've said and pitchschift the results to create a melody. It'll then set this against a backing track to build up an entire song.
The results can be a bit mixed, but the app is heaps of fun to use, especially if you're just messing around with it with your mates. If you don’t like the initial track it creates you can ask the app to re-Songify the results, but unfortunately there are no real editing tools to tweak the overall results.
Songify won't help you launch a music career, but it is a lot of fun to mess around with, especially with a bunch of friends.