After launching the emulator (ensuring that sound is unmuted), allow the Mac OS to boot and then... do nothing. After one minute of inactivity, After Dark will kick in.
This emulated Internet Archive item contains version 2.0 of After Dark, the software that kicked off the screensaver craze of the 1990s. Additionally, the expansions "More After Dark" and "After Dark - Art of Darkness" have been added to the install.
Navigate to the After Dark control panel via the Apple menu where you can change to a different screensaver module, change settings for each, and demo them all without having to wait for a minute.
I am particularly fond of GraphStat.