GB Test Lab is a diagnostic cartridge for the original Game Boy. It checks functions including memory, interrupts, cartridge-slot lines and button contacts, while its Quick Check runs several autonomous tests in under a minute.

Results can be stored per console, and a connected Game Boy Printer can produce a six-page report on thermal paper. The cartridge also contains twenty reference articles explaining Game Boy components and symptoms.

Throaty Mumbo built a custom GBCTube cartridge to play YouTube video on a Game Boy Color's 160×144 display. The project progresses from displaying images and video to streaming over the link cable, then adds custom Wi-Fi-capable hardware.

The video demonstrates playback on real Game Boy Color hardware and covers the cartridge electronics, battery and enclosure built for the project.