Liven up the wait during rendering with this add-on by Jason van Gumster!
Jason van Gumster writes:
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.