There are the computer based ones you can do with a 20x20x20 or even up to a 100x100x100 cube. I break them down to the algorithms and shorthand ways. I can solve a 3, 4, or 5 in about 3-4 minutes. My record for a 20 was almost 3 hours, and the 100 took a few days added up to about 22 hours total. Boredom leads to strange hobbies. I can try to find the program if anybody is interested.