Puzzle Tutor... it's still live though. Well, the main aim was to help speedcubers from across the world with one-on-one expert coaching. Our team, a mere conglomerate of 3 friends who loved solving Rubik's Cube became the co-founders of Puzzle Tutor. 

But after the Product came to the System, we failed to generate enough exposure to get inbound clients. And later on, it failed... 

But failure teaches you more than success... And here's everything I learned from starting up at the age of 15 :)