Here is a really sad one I don't think works on sapphire/ruby.
Go to Petalburg Poke Centre. See the gentleman standing by Joy? Talk to him 101 times in a row without moving away from him - just bash A if you like -, he will say after this 'I reckon u can use the pc now' and then if u check box 8 there's Jirachi in it. And here's another. When you get up to the 50th successful rocket launch, go to Littleroot, talk to Birch 50 times, and then the rocket that takes u up to space to catch deoxys and jirachi - which works - will land outside your bedroom.
Here's another sad one I made up - the site that takes you to a cheat that tells you how to catch all pokemon just by catching a pikachu.
www.celebiwishmakerjirachi.puzzleds...ode_0021_Dark_Alakazam_Rider/PikachuScore.com. The person I told it to believed it. They actually tried it out. For heaven's sake!!!
Also what about this one? Chemicho is caught by hatching the egg of an Absol with a Swampert at the top of Mount Pyre. Out comes Deochi, which uses the pokenav as a pokeball to catch chemicho. if you have only deochi and absol in your party chemicho and its evolutions, Gigacho, Ferraacho, and Snaggachimchotti are in ur party. (I made that up. Haven't tested it yet.)
Here's another crazeeee one I made up and tricked the Puzzledsheep-pichu one with. Erika had a son and on FR/lg she let her son, Sagamori (pronounced Saj-a-more-ee), take over, who uses flying pokemon. Gosh, some ppl are off the planet to believe these!
Also I think it is sad th@ some cruel ppl would post pranks like that to catch little kids - referring to the cheats/rumors. I mean, the majority of them are 'put your game boy in the microwave' or 'smash it up with a jackhammer' etc. etc. etc. C'mon, poor little kids who put their gb in the microwave... SHAME ON YOU PPL WHO ACTUALLY MADE THOSE UP AND POSTED THEM! hehe