Playing local MP3s in Chrome OS

I e-mailed myself an MP3 today, and while I could it play it in GMail, I couldn't do anything with the file once I downloaded it to the Cr-48's hard drive. Then I remembered the experimental Media Player feature. By typing, "about:flags", into the address bar, I was able to list Chrome OS's experimental features. After clicking enable under the Media Player text -- and then restart -- the feature was installed. All I had to do was find my downloaded files again, by pressing Ctrl + O (not zero.)

Note: Closing out the Media Player won't stop the music.  You have to press stop.