Idea
Add a mod to play sound files+status
Add a mod to play sound files+priority
Add a mod to play sound files+tag
Add a mod to play sound files+issues
It's easy to upload an audio file to Wagn, but not easy to play it.
Add a mod to play sound files+solution
Here's one JavaScript player: http://scmplayer.net/
A simple solution would be to use that or something like that, pick some defaults, and just make it so that any File card that is a sound format that the player knows renders in content view with a player and a link to download. A more complex solution could offer a new Audio cardtype with multiple fields to let Wagneers and editors set options on how the player appears, whether it offers the download link, etc.
In either case, one question is whether to bother with pre-HTML5 compatibility.
Add a mod to play sound files+discussed in support tickets
Add a mod to play sound files+relevant user stories