Surfing Pikachu is a very sought after pokemon, because it knows a great move for countering it's only weakness (which is ground): Surf. However, until now, it was only available from Nintendo Events, meaning that for most people, it was impossible to get one.
But, it is now possible to get Surfing Pikachu without going to a Nintendo event. How ? With Pokemon Battle Revolution, of couse ! You can get Surfing Pikachu after you have completed the main game from the lady a the desk. And there's no catch at all. No Nintendo Events, no really tough battles, no unexpected payments of large amounts of money to Nintendo. No nothing. Apart from a very cool Pikachu which also knows Volt Tackle, a great move which was previously unavailable (in the same moveset as Surf) because Surf is an event move and Volt Tackle is an egg move. Finally, the Pikachu has a Light Ball attached, which doubles it's attack. And that's another reason to buy the somewhat rubbish OK Battle Revolution. It comes at lv. 10 and in the trainer memo it says: it came across a fateful encounter at lv.10