Last month, an excellent promotion was revealed for Mario Kart 8 that would give gamers a choice of one of four free full games from Nintendo, just with the purchase of Mario Kart 8. However, the insane rush for this promotion has started to cause a lot of issues with the Club Nintendo website, so be prepared for some issues.
The promotion states that by registering Mario Kart 8, either through a PIN from the retail or having your system linked through digital, you have the option to download one of four free games: New Super Mario Bros. U, The Legend of Zelda: The Wind Waker HD, Pikmin 3, and Wii Party U.
There have been reports of some people registering their PIN and then not having it show up in their account but when trying to do the PIN again, it shows up as already used. To be safe, you may want to wait a few days while things are sorted out. The Club Nintendo site has suffered a lot of downtime and still is down about half the time when I’ve checked on it, so definitely be patient if you are trying to register your copy of the game.