Starting this week, and last week, there are two event Pokemon available at retailers in Japan now. Both of which use serial codes to receive, so you can only do this with a Japanese copy of a Gen VI title (X, Y, OR, AS).
黒いレックウザ
You can get a shiny Rayquaza one of two ways. You can go to any participating retailer in Japan, show them your copy of a Gen VI game, and get the code. Or you can go to Seven Eleven, and a get a code through Nintendo Zone.
Unfortunately, it does not come with a Mega Stone. You have to collect the stone in game from that elderly Dragon woman at the end of the Delta episode. I'm not sure if she gives you for each Rayquaza you have, but you only really need one.
アルセウス & フーパ
As part of promoting the 18th Pokemon movie, coming out in July, if you buy a prepaid ticket, you will immediately get a code for a random Arceus, and able to get Hoopa later on.
There are 18 possible Arceus you will receive, and each one has an equal chance. 16 of the possibilities are Arceus holding a plate, which changes its type. The remaining two are Arceus holding a Silk Scarf. One of those two are shiny. So, there's a 1 in 18 chance of getting a shiny Arceus.
I got a Ghost Arceus. Oh well.
Unlike most event Pokemon, you are able to enter as many of these codes as you want, and continue to receive more and more Arceus. One is enough for me, though, thanks.
As usual, I found out about these Pokemon through serebii.net. Though, Bulbapedia had more useful information. Bulbapedia had links to each Japanese page with location details, and step-by-step instructions on what to do when I got there.
For Black Rayquaza, they pointed to a list of all retailers that carried the serial code cards. And my local Takayama 高山 Apita アピタ was on the list.
岐阜県 - アピタ 飛騨高山店 - 岐阜県高山市国府町金桶41番地
Apita is a kind of mall in Japan, though many of the internal stores are Apita brand stores. It's also completely open inside. There are no walls (or few walls) separating the different stores, and departments. I guess it's really more like a department store, but different departments are sometimes subsidized to different companies. It would be like if Wal*mart didn't actually carry video games, but allowed Best Buy to sell them in their building instead.
Near the south entrance, next to Baskin Robbins, was the toy department, Joy World. Displayed promptly in the front aisle was just what I was looking for.
The instructions were at the bottom. タイトル画面をお店の人に見せよう! "Show the title screen to a shop keeper" ソフトの数だけシリアルコードをもらえる! "You can receive one serial code for each game." I think that's what that says. Those are the exact directions from Bulbapedia.
I turned around, and went to the service counter. I talked with the clerk, showed him my game, and got the goods.
If you don't have an Apita nearby, nor any other store on that list, you can do the MUCH easier option, and visit your local Seven Eleven, and get a Black Rayquaza code digitally through the Nintendo Zone.
This one was just a block away from Apita. I got an extra Rayquaza code through this way just to check out the process. But this is where I also got my Arceus.
You can buy prepaid movie tickets at Seven Eleven. And to do so, you need to find their copy machine. The copy machine doubles as their Internet commerce machine. You can buy movie tickets, concert tickets, pay for things online, and whatever. The Pokemon Movie thing had an ad on the front page.
I selected the ticket, brought the receipt to the register, paid for everything, and got the goods.
A 1400円 ($14) prepaid ticket, and an extra ticket with my Arceus code. The extra ticket also has some slip for getting Hoopa on June 20th. Apparently, I need to go to one of the locations listed in the guide with this slip, and do something. Whatever, that's a problem for Future Jim.
Hurrah, Pokemon. I have two new event Pokemon to add to my collection with Hoopa, the 720th Pokemon, coming in the future.
I can totally see both of these events coming to the U.S. Gamestop could easily get a bunch of Black Rayquaza codes to hand out to people. And the Arceus event is tied in with the Hoopa movie. Gamestop could probably have codes for that as well. I dunno.
The Black Rayquaza event is part of an entire campaign. You can get a Black Rayquaza card for the Pokemon TCG. There's one for the Moncolle thing, too, and some other limited toys. I don't live near a Pokemon Center to do any of these things. But luckily, Pokemon Center has a store page on Amazon. As part of the campaign, they made a limited shiny version of the Mega Rayquaza plush. So, I bought one.
And this thing is WAY bigger than I thought it would be. It was 3600円 ($36), and stretches over a meter in length. There are water bottles in those shots for size comparison.
It has a skeleton inside, too, so you can bend and pose the plush however you'd like. I tried to coil its body so it actually stands up. I have it wrapped around a Kappa yokai in the corner of my bookshelf.