Seriously though, if you don’t mind doing a little reading I would suggest this article which explains building a pop up mp3 player that the user can shut off. I think it comes across as being pretty slick without any fancy coding.
There’s links to some other articles in there which have different methods for building players.
Keep your bandwidth in mind. The reason that a lot of old sites would use midis in the background is because you didn’t have to stream a very large file to all your users. Once you start streaming an mp3, assuming you’re on a basic shared server webhosting, you’ll be able to stream the audio to maybe five or ten people at the same time before it starts to crack and sputter (for everyone).
If you’re hosting the webserver on Apache at your own house, it might be less then that.