This is a goofy little add-on that surprisingly took more work to create than I expected. Basically, it plays elevator music while you render. And when the render is complete, a bell rings.
Usage notes copied from the add-on’s wiki page:
While rendering, “elevator” music automatically plays. When the render job is complete, a bell rings.
You can optionally enable and disable the music and bell from the Render panel of Render Properties.
From the Files section of User Preferences, you can specify different sounds for the render music and end tone. Any sound file that Blender recognizes (WAV, MP3, OGG, AIFF, etc.) is supported.
Note: This add-on will not work on Blender builds prior to r44810, so fire up your compiler (or get a recent build from graphicall.org).
Direct download link: Render Music Add-on
Special thanks to Sam Brubaker (rocketman on these forums) for custom creating the music that’s packed with this add-on.