A discussion on eReaders, Mystery Gift, Enigma Berries, and the sorts.
As you may know, the 4th generation's Pokémon games' save format has been cracked open and documented immensely - this means we know about how Mystery Gift works, how to generate a Pokémon and distribute it via Wonder Card, open event wonder cards, and more. The same hasn't been done to any of the third generation games (and if it has, hacking information for them simply hasn't been documented), and that ought to be solved.
There's a laundry list of mysteries (ha ha ha.) that are relating to external events:
Wonder Cards. The important feature. Distributed Wonder Cards are able to activate in-game events such as Deoxys, Lugia, Ho-Oh, and in Emerald, Mew. They can (I assume) also be used to distribute items.
Wonder News. The less important variant. These can be used to distribute notices or long passages of written information.
Card-e events. Used to activate Southern Island event (Ruby, Sapphire and Emerald only), activate specific berries and activate special trainer battles (limited in FireRed, LeafGreen and Emerald).
Emerald Card-e+ events. While limited in the English versions, Emerald allows for its own special kind of maps to be used in Trainer Hill.
Record Mixing. Any events activated in Ruby/Sapphire/Emerald can be distributed a limited number of times via Record Mixing.
And speaking of Record Mixing, TV in FireRed and LeafGreen, and its relation to an old man in Cerulean City.
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