Recently I bought a Gameboy Advance SP (I was playing some of my old games and got tired of the screen being so hard to see.) Being the nerd I am, one thing I keep wondering is what the code looks like behind the games. I'd imagine it's not too different than any other assembly language.
I don't have the patience to learn everything about assembly, so I got looking into other programming languages for GBA. Come to find out there are a lot of people who use some libraries and compilers to write their games in C. So guess what I'll be doing for next few months? 
Working with things like Javascript and PHP all day, the syntax of C makes perfect sense but I'm a bit rusty on the actual code. So I'll be working on trying to brush up on my C and spit out a working game. Any ideas? I'm thinking of starting out small with little slot games or something and working my way up to an RPG.
The Pern Project - Full of tools and tutorials on Gameboy Advance programming.
Visual Boy Advance - A nice GBA emulator, useful for testing compiled code.
If anyone has a good tutorial on Gameboy or Gameboy Color programming, could you send me the link? I wanted to start out with a more simple system but I can't find any good tools and tutorials on it.
One thing I don't like is having to run Windows in virtualbox to run the development tools. If I find a good Linux development suit I'll post it. Read more about Programming for the Gameboy Advance
