Apple’s Pippin Game System booting to Marathon
One of Apple's dazzling failures, the Pippin @World or Atmark, produced by Bandai (the Power Rangers people) and briefly by Katz Media, was to be a TV set-top box/game system with Internet connectivity. It was a barely disguised PowerPC-based Mac, with modified (ruggedized) ADB ports, and flash memory in place of a hard drive. It ran a modified version of Mac OS 7.5.2 which was contained, in its entirety, on each game CD.
Here's a Pippin booting to the classic Bungie game, Marathon...
Apple’s Prototype Copland OS Booting
This was intended to be Mac OS 8, a microkernel (called NuKernel) based OS that would finally modernize Apple's aging technology stack. It failed, although several of its user-oriented components made their way into later versions of the OS (both Classic and OS X).
This is booting off a PowerMac 7600/66 AV, but connected to a Dell LCD monitor so you don't have to see the refresh. It boots to the "Z Theme" which was a little silly. During start-up you can see a very unique splash animation, and various hardware being identified and initialized.
Copland was to contain a "blue box" emulation layer for classic Mac apps -- a concept that would later be re-used as "Classic" in Mac OS X -- while next-generation apps would be optimized for the PowerPC CPU.