I like finding out about the insides of games. For example I have the Sims (1), but I have spent most of my time experimenting instead of playing the game.
Well, I have played Yellow and Blue all the way through and most
of Crystal. I found out about the misnamed Mew Glitch. Since as yet there is no way to get any of the legendary pokémon from eggs, and I have only read somewhere (the Nintendo Diamond/Pearl Guide, I think) that dittoes can breed, level 7 is the lowest you will be able to get any of these except for a mew. So I now am the proud trainer of a ditto (Metamon), an articuno (Freezer), a zapdos (Thunder), a moltres (Fire), a mewtwo (Moonwatcher), and a mew (Trickster, I think I’ll change it to Devil though) all at level 7.
As a true pokémon researcher, I am keeping track of their progress under stict conditions just to see what will happen in the early levels. Unfortunately there is no way (that I know of) to port these pokémon beyond Crystal. I have a post on my site for anyone interested. I need to update it as they are now up to level 18, but I am having difficulty with the HTML code for the tables. I am working on it though.