A nice marketing strategy to help Nintendo's console.
Anyone who owns a Wii U will most likely pick up Mario Kart 8. Specially if there's a special edition with a blue shell statue like it was mentioned months ago but so far nothing else has been mentioned since. Now Nintendo is offering a sweet incentive to pick up Mario Kart 8 and register it with Nintendo before July 31st, A free game. You will get 1 free download from: New Super Mario Bros, Pikmin 3, Zelda: Wind Waker and Wii Party U with Wii Party U probably being the most unpopular one.
European gamers though always seem to get the great deals recently with more games to pick from:
Although to be honest you can pick up most of them for under $20 on a good day on amazon.