I have just found this new 1-bit music blog explaining what's all that beeper music about.

I heard about 1-bit music some years ago only; since I never owned an Sinclair Spectrum, and never got to play with one in a silent environment (i.e. not in a mall) I never knew how did the Spectrum's beeper sound like.

I believe the (first and) last time I heard about 1 bit music I also was able to download a ZIP file containing several beeper tunes, but since I don't know which site it was, here's a sample song from the author of the blog (Shiru) at 8 bit collective: River City Rancor

Now I wonder if there's some sort of similar stuff for Arduino. It might be an interesting project to experiment with very lo-fi music.

Update (a few minutes later): maybe that site I mention was this one which has a bunch of 1-bit music from various almighty composers such as Ben Daglish!