Produced by Triton Labs, the Afterburner is a modification kit for Nintendo's Game Boy Advance (aka GBA).
Many people have expressed disappointment with the GBA's screen - it can be difficult to find a viewing angle where the screen reflects enough light. External lamps are available, which plug into the unit and draw power for a small overhead light. However, these are not an entirely satisfactory solution, producing uneven light on the screen (and, frankly, they look stupid).
The Afterburner kit seeks to remedy this. It is a light that fits inside the GBA, lighting the screen from within so that it looks like the traditional back-lit displays found on the GameGear and Lynx.
This, of course, requires you to void your warranty by taking your GBA apart and physically soldering the kit in place. However, if you've never handled a soldering iron, never fear - some companies will be offering pre-modified GBAs.
The Afterburner draws power the same way as an external light, so the battery power drain is the same as any external lighting solution. It also includes a dimmer dial, so you can use as much or as little extra light as you need.
Update 25th June 2002
I've just finished installing my afterburner! It wasn't quite as nightmarish a procedure as I was starting to fear, having read the Triton Labs forums. Nevertheless it's serious business - it does involve a fair bit of soldering , not mention cutting great chunks of plastic out of the inside of the GBA.
The results are wonderful - an even light over the whole screen (except, in my case, for a tiny bright spot caused by an air bubble in the anti-reflective film). The included potentiometer gives excellent control over the screen brightness. Also, apart from the extra dial, you can't tell that the GBA has been modified at all until you turn it on (which I find incredible after the rather dramatic procedure it's just undergone).
Overall, a big thumbs up, but you might want to get someone else to install it if you're not reasonably handy with a craft knife and a soldering iron.
See http://www.tritonlabs.com for more details. Alternatively, drop me a msg with any questions (if you want to know more about the installation procedure, for example).
Update 2006-04-07 : I think this might have gone out of production. The new GBA SP has a built-in light so it is redundant, really.