Did you know the first two Pokémon sequels were supposed to let you ride a skateboard?
It was advertised. Briefly. Then....just quietly removed and never spoken of again. Turns out it's still in the game's code, though, so in addition to combing through old Japanese mags for mention of the item, Aria over at Glitterberri has translated some fan's testing of the skateboard's unused code left sitting on the cartridges.
Pokémon historians, it's well worth a read.
The Case of the Missing Skateboard [Glitterberri]