So, I put the thing in my pocket and promptly forgot about it. I just noticed it again tonight, so I dusted it off, replaced the battery and surprisingly, it works just fine! In addition to having enough memory for 64 MP3 songs, it even plays FM radio and has a built-in microphone for recording spur-of-the-moment ideas. The whole thing is quite small - about the size of a lighter - in fact, that's what I first thought it was when I saw it on the ground.

I wasnt sure how the MP3 files could be transferred to the thing - I couldn't find any obvious connectors or sockets for plugging in a cable. Then I decided to pull on the thing and it turned into a USB drive! It looks like this when pulled apart:

So, it's really quite simple to transfer stuff to and from it. It's a pretty cool design - I feel bad for the person who lost it.