Gameboy Advance
The Gameboy Advance[1] was Nintendo's third in the Gameboy family of handhelds, released on March 21, 2001 in Japan, and on June 11, 2001 in North America. The was the successor to the Gameboy Color, and in turn, the Gameboy. It was later succeeded by the Nintendo DS line.
The Gameboy Advance was a shakeup for the Gameboy line, shifting away from the vertical form factor of the original and the Color, and instead opting for a new horizontal landscape that provided a more ergonomic design to the handheld. It also jumped from an 8-bit processor in the DMG and Color, to a 16-bit/32-bit hybrid processor. A notable philosophy of the GBA is the idea of having lesser features built in, but offering higher-end features as an add-on. The system ran on two AA batteries, but Nintendo sold a rechargable lithium-ion battery pack that replaced the usual battery cover. The system had a built-in mono speaker, but was designed to be able to output stereo audio if connected to a stereo output via the 3.5mm headphone jack (some games specifically supported this by offering in-game audio settings, either explicitly noted as "Mono or Stereo" or sometimes denoted as "GBA or Headphones". Some later games such as Rhythm Tengoku refered to stereo audio as "DS mode" audio). The GBA continued to use link cable technology for most of its life, akin to the Gameboys before it and also the GameCube-GBA link cable, but later Nintendo also offered an IR-based wireless adapter for the system that served as a link cable alternative (support for this accessory was low, but did prominently feature Pokémon FireRed, LeafGreen, and Emerald).
It launched with a notable variety of games, including some very solid titles, such as Castlevania: Circle of the Moon, ChuChu Rocket!, F-Zero Maximum Velocity, and Super Mario Advance. The library of games continued to expand to inlclude hundreds of popular titles, and widely helped carry Nintendo through the GameCube generation, as both home console and game sales faltered. To try and bolster GameCube sales, Nintendo utilized the GameCube-GBA link cable, adding functionality and connectivity between not only the Gameboy Advance and GameCube, but also some GBA and GameCube games. The GameBoy Player was also an accessory released for the GameCube that allowed players to run their GBA cartridge games on the TV using the GameCube as a control deck, using either the GameCube controller or the GBA via link cable.
Gameboy Advance SP
A notable shortcoming of the GBA was the fact the screen had no front or back lighting, making visibility difficult under various circumstances. Nintendo later released an upgraded version of the GBA titled the Gameboy Advance SP, released on February 14, 2003 in Japan, and on March 23, 2003 in North America. The first models (AGS-001) featured a frontlit screen that could be toggled off with a new brightness button. It also featured a clamshell design for the first time on a Nintendo handheld, opting for a vertical form factor like the original Gameboy models, with a hinge to allow it to become more compact, shifting the cartridge slot to the bottom of the system to make room for the new hinge. The SP also added a rechargeable battery standard (complete with a new charger), retained the GBA's link cable and wireless adpater connectivity, retained the mono speaker built-in, but sadly cut the 3.5mm headphone jack. Nintendo later offered an adapter to be able to connect external audio output via the charging port. A later SP model was released (AGS-101) that featured a frontlit screen with two brightness settings, both brighter than the AGS-001, with no option to turn it off.
In May 2004 at E3 2004, Nintendo revealed the Nintendo DS, which furthered the design and features of the GBA SP and evolved them into a new family of handhelds.
Homebrew
As with consoles before it, the Gameboy Advance is capable of running unofficial software, but requires a flash cartridge such as the Everdrive or EZ Flash in order to do so. The GBA is an incredibly popular platform for things like Pokémon ROM hacks and fan games, such as Pokémon Radical Red, and Super Mariomon.
A common practice with the GBA is to mod the system to feature a backlit screen for more convenient gameplay. This can be done either by using a GBA SP screen, or an aftermarket IPS screen. Both require a ribbon cable adaptor, but can be done even by novice modders with the proper guide.
About
The Gameboy Advance was my very first handheld as a kid, so obviously I'm very fond of it. I got it with a copy of Namco Museum, and A Link to the Past & Four Swords. The combination of arcade, high-score-based games, and the sprawling adventures of Hyrule and the Dark World, plus the portable factor of playing my games anywhere, whenever I wanted, truly made me fall in love with gaming. It was the first time I ever used a computer to look up new games I had never heard of, and look for ways to buy said games. It really was a turning point for me as a young girl to play Pokémon for the first time, or discover Super Mario Bros. 3. My early love of the Gameboy Advance propelled me into the world of gaming, and helped bring me to where I am now.
This is in no small part thanks to both the comfortable form factor, and the incredible lineup of games, not to mention the ability to play any Gameboy or Gameboy Color games. Mario 3 and Zelda alone would have carried me through my childhood, but I discovered my lifelong love for Pokémon along the way, as well as franchises like Kirby, F-Zero, Sonic the Hedgehog, Fire Emblem, Metroid, Castlevania, Rhythm Heaven, WarioWare, Final Fantasy, honestly the list could keep on going and going, but you get the point. The GBA is a fantastic system on its own, not to mention how many wonderful games released for it. It felt like no franchise was lacking on the GBA, and there truly was something for everyone. If you're a gamer of any kind, I recommend checking out some GBA games in whatever way you can. I promise it's worth your while.
Footnotes
[1] The official stylization is "Game Boy Advance". I recognize this, however I think it looks way worse than Gameboy, and I will continue to use my own stylization for it.