RetroPie
One of my more entertaining projects involved a Raspberry Pi 4 with 4 GB of LPDDR4-3200 SDRAM, an ARM based Quad Core Cortex-A72 64-bit SoC @ 1.5 GHz, built in 2.4/5 GHz IEEE 802.11ac wireless connectivity, Gigabit Ethernet, Micro-HDMI with a maximum output of 4K @ 60 Hz, USB-C power with USB-A 3.0 and 2.0 ports, and a 128 GB Micro SD card. I received this Raspberry Pi 4 as a Christmas gift before and I've used it for exploring many different development projects (including a custom operating system at one point). I've since moved the majority of my development and coding suites over to my principal desktop, so I decided to pursue a different avenue with my Raspberry Pi.
My goal was to turn my Raspberry Pi into the ultimate retro gaming console, similar to the likes of the NES mini and Playstation Classic, only better, since the Pi would be able to emulate more than one system and it would support native side-loading of whatever games or game collections I would choose to add. For this project, I decided to go with RetroPie, since it supports a vast array of retro consoles that I enjoyed as a child and even some that I'm interested in exploring for the first time, including the Amiga 500, Atari 2600, Commodore 64, Sega Dreamcast, Game Boy Advance, Nintendo GameCube, original Game Boy, Game Boy Color, Sega Genesis, Classic Macintosh games, MAME, Nintendo 64, NES, Classic PC Games, Playstation 1, Playstation 2, PSP, SNES, and many more. I loaded RetroPie onto my SD card using the Raspberry Pi Imager and I was on my way to having a full custom game console!
The setup was relatively straightforward, however, it did require some configuration to have the system run properly and to install ROMs directly to the SD card (as opposed to running off a USB thumb drive, so I can keep my Pi as self-contained as possible). So far, I've only used the Nintendo 64 emulation, however, this project has brought me a lot of enjoyment in my leisure time!