A few years ago I've purchased the GBA Movie Player. While it was kinda fun to watch a few movies, listen to MP3s, and look through images on my GBA SP, and yet the fun wore off pretty quickly.
When the Nintendo DS arrived some people quickly developed the first ways to hack into the system, things like FlashMe and PassMe appeared, but both required too much effort and had some risk that your DS would get broken or at least the warranty would dissolve.
And now Reboot and Janis sent me a link to the M3 DS Simply - and I finally can turn my DS into the kind of gadget it should have been from the beginning. Watch movies and images, listen to MP3s, run DS Roms (!), and homebrew stuff like ScummVM (!!) and DSOrganize (including an IRC client and a webbrowser), both of which you can get at H4ndy's Homebrew Site.
I'm so happy now! *_*