Pokemon glitches are arguably the best... the weird Pokemon you can get out of them! I once saw someone that obtained a Lvl. 173 Golduck or something like that.
btw, has anyone ever seen Bad EGG? That is a really damaging glitch, and it's for Ruby/Sapphire/Emerald... I'm not sure about FR/LG. It's an egg that duplicates, filling up all your boxes and not allowing you to catch more Pokemon. It will either not hatch and just stay there forever, or hatch and destroy your game. The only way to obtain it if you put in a code to get a rare legend (eg: Deoxys, Jirachi, Mew) and mess up. Sort of an extreme punishment for cheating. :\
I have a "Bad EGG", and it's definatly not a punishment. It's a glitch in the game that causes pokemon that are obtained through cheat codes to become "place holders". The reason it's called Bad EGG is because the data the CPU recognises is invalad, so the name is changed to Bad EGG as a way of letting the player know that it's "abnormal".
H4xx0rs know all about this stuff.