The games I don't own:
Earthbound, Dr. Luigi (because I bought Dr. Mario twice already), Fluidity Spin Cycle, Donkey Kong 3.
I admit, Donkey Kong Country for 3DS is a hell of a prize and anybody that doesn't own it needs to buy it. For me, the options are severely limited. I guess I'll go with Earthbound since it's legendary. But registering hundreds and hundreds of dollars in games to earn a $10 download is madness!