Activision Anthology Remix Edition is a commercial release from Activision which packages an Atari 2600 emulator for the GameBoy Advance along with a very good amount of games, including my homebrew Space Treat.
The emulation is a real piece of art and manages to almost perfectly recreate the 2600's behaviour on the really limited GBA's hardware (limited CPU mostly).
It's really great to have a portable 2600 emulator!
GBallz is my first homebrew game on the original B/W Nintendo Gameboy. It was coded in C using the lightweight LCC compiler and I must say that I've had a blast doing it.
As usual it's not really complete (lacks sound and quite a few levels) but 99% of the code is there and the game is playable.
I've later recreated it as Bounce! on the Atari 2600.