Burp Construction Kit by HCA, released in April 1987, for the Commodore 64 - When I was a kid, I had a ton of fun with this sound demo that made the C64 create all kinds of burp sounds.

This is the demo program you'd see running on a Commodore 64 when you'd go to a department store or similar.

Just a few of my BASIC demos.  :)   Uses DirMenu to execute my programs.

If you are fortunate enough to have an Ultimate 64 by Gideon, you absolutely MUST play this demo released at the 2019 Evoke competition. It's so amazing to hear 8 SID chips (24 channels) all playing at once! 

In this particular archive there is a .cfg file you can load into your Ultimate 64 that will configure the settings you need to make this work.  If you'd like to preview the demo beforehand, here's a YouTube link.

Wall of Sound by Bad Boy of Reflex - This is a pretty neat demo of the wide range of sound effects and music you can produce with the Commodore 64.

Xtreme Mega Comeback II by Camelot is another 256 byte demo released in August 2003.  This demo is bouncing raster bars with something hidden.

Xtreme Mega Comeback by Camelot is a 256 byte demo released in August 2003.  Pretty neat bouncing comet with a trailing tail using just standard keyboard characters.