I really like the Thrill Digger in Skyward Sword. There's basically no point to playing it, but I can just play it over and over without getting tired. There are so many better ways to get rupees in the game but I'm addicted. It's like an imperfect version of minesweeper since you never know exactly how many bombs are near a rupee. I always play on beginner since that's the only one in which I can actually use logic sucessfully to earn rupees. Still with how much I've played it, I've only had one perfect round- meaning I found all the rupees and had nothing but bombs left- and that gets you a random treasure. So basically the game is nowhere near worth playing to earn money, but I love playing it anyway.