As Nintendo has announced this morning/yesterday evening, they will shut down their Wi-Fi Connection services for many Wii and NDS games on May 20th 2014. 3DS and WiiU games are not affected. The whole list of games that are affected is in the announcement below. Source: Nintendo.com [quote author=Nintendo.com] Nintendo Wi-Fi Connection service for Nintendo DS and Wii to end in May 2014-02-26 As of May 20, 2014, certain online functionality offered through Nintendo Wi-Fi Connection will no longer be accessible. The discontinued services include online play, matchmaking and leaderboards for many Wii, Nintendo DS and Nintendo DSi games. For a comprehensive list of games and services that are affected, please check http://support.nintendo.com/servicesupdate. Users can still play the games in offline mode, which continues to offer a rich game-play experience. Online play for Wii U and Nintendo 3DS games will be unaffected (aside from the Wii mode on Wii U and Nintendo DS games on Nintendo 3DS family systems). Other online functionality, such as access to the Wii Shop Channel, the Nintendo DSi Shop and video-on-demand services, are also not affected at this time. We at Nintendo sincerely thank our fans for their continued support of our company’s legacy systems. Your enthusiasm for games made for these systems speaks to their longevity, and the passion of Nintendo fans. List of affected Nintendo software titles Note: Game functionality that does not require an Internet connection will remain unchanged. Nintendo DS 100 Classic Books Animal Crossing: Wild World Advance Wars: Days of Ruin Clubhouse Games Custom Robo Arena Diddy Kong Racing DS Dragon Quest IX: Sentinels of the Starry Skies Dragon Quest Monsters: Joker 2 Fire Emblem: Shadow Dragon Fossil Fighters: Champions Legend of Zelda: Phantom Hourglass Mario Kart DS Mario vs. Donkey Kong 2: March of the Minis Mario vs. Donkey Kong: Mini-Land Mayhem Metroid Prime Hunters Personal Trainer: Walking Picross 3D Picross DS Planet Puzzle League Pokémon Black Version Pokémon Black Version 2 Pokémon Diamond Version Pokémon HeartGold Version Pokémon Mystery Dungeon: Explorers of Darkness Pokémon Mystery Dungeon: Explorers of Sky Pokémon Mystery Dungeon: Explorers of Time Pokémon Pearl Version Pokémon Platinum Version Pokémon Ranger: Guardian Signs Pokémon Ranger: Shadows of Almia Pokémon SoulSilver Version Pokémon White Version Pokémon White Version 2 Professor Layton and the Curious Village Professor Layton and the Diabolical Box Professor Layton and the Last Specter Professor Layton and the Unwound Future Star Fox Command Style Savvy Tenchu: Dark Secret Tetris DS WarioWare DIY Nintendo DSiWare Mario vs. Donkey Kong: Minis March Again! Metal Torrent Number Battle Wii Animal Crossing: City Life Battalion Wars 2 Endless Ocean Endless Ocean 2: Adventures of the Deep Excitebots: Trick Racing Fortune Street Mario Kart Wii Mario Sports Mix Mario Strikers Charged Pokémon Battle Revolution Samurai Warriors 3 Sin & Punishment: Star Successor Super Smash Brothers Brawl Wii Music* WiiWare Dr. Mario Online RX Excitebike: World Rally LONPOS Maboshi's Arcade My Pokémon Ranch ThruSpace WarioWare DIY Other Wii Speak** Wii Speak Channel** (*) Services that require Internet communication ended on June 28, 2013. (**) As Nintendo Wi-Fi Connection is required to use this title, it is no longer functional [/quote]
To be fair, they stopped making DS games a while ago. It's a real shame though; playing online with others made the games that much better.
Apparently quite a few games have functionality; even DS Download Content is available for most games
Instructions on how to connect a custom server https://github.com/polaris-/dwc_network_server_emulator/wiki More Info about this project at http://save-nintendo-wifi.com/
It is still possible to play wii games online through ~ wiimmfi ~ its a program that takes the place of nintendo WFC and connects to a different server that fans have so kindly set up and allowed just spell it like up there then .de instead of com