The Nintendo DS is the latest and possibly most popular handheld game system from Nintendo. As has become tradition with just about every game system, there is a large and active homebrew community making all sorts of tools and toys for it. We've gathered 20+ examples of some of the things your favorite game system for those on the move can do that you may never have known about.
Make sure to read the instructions for each as some require different homebrew installs than others. The DSWiki has detailed directions on how you can get in to the homebrew world.
Art
Animanatee - An animation program that allows up to 10,000 frames of animation, or until the memory runs out.
Colors! - A pressure sensitive art program that you can save your artwork via memory card or email it over Wi-Fi.
FlickBook - A simple animation program for making small animations.
Phidias - An art program that lets you create detailed images saved to the BMP format.
Communication
DS-AIM - A version of AIM for your DS.
IRCDS - Internet Relay Chat comes to your handhel.
SvSIP - A VoIP tool based on Session Initiation Protocol (SIP). Still in development and only handles basic phone functions at thi time.
Emulators & OS
DSLinux.org - If it's electronic, somebody stuffs Linux in it, and the DS is no different.
DSMouse - Turn your DS into a wireless mouse for your computer.
Emulator-Zone.com - A repository of several emulators for the DS.
Goomba - An emulator to run original Gameboy games on the DS.
SnezziDS - Away to run Super NES games on the latest iteration of the Nintendo handhelds.
Utilities
DSFTP - Allows you to set up an FTP server on your DS, also includes instructions to incorporate it it into other homebrew programs.
DSLiveWeather - A client to access Weather.com's weather information.
DSOrganize - A lightweight organizer for your DS that also includes a RSS reader, file browser, web browser, IRC client, text editor, calculator.
DSReader - Another popular ebook reader that also allows you to turn the DS sideways to read it in more in the orientation of a traditional book.
DSVNC - A VNC tool to allow you to control a computer over a private network from your DS.
Image Viewer - From the same homebrew group behind Moonshell, uses an app on the computer end to convert photos for better viewing on the DS and then gives you a viewer inside the DS.
Moonshell - A popular media player that can use MP3, OGG, MIDI, AAC and other audio file formats. Can also show JPG, BMP, GIF, PNG, TXT files and some videos.
TextViewer - Can read several file formats and allows for text bookmarking so you don't lose your place.
Treasures of Gaia - A Google Maps application that works both in French and English.