I have been toying with Cakewars in an MPS, and made up a fun game called bone hunt. I think it would be a really fun nano game. Basically, you start out in a barrier container. In-front of you is a big (14x14x14) cube made of brown wool, with 8 "Bones" in it. A bone would be a 2-block-long structure, made of endstone. You start out with haste and shears so you can insta-mine wool, and whoever finds all 8 bones first wins the game. The bones are evenly scattered within the block of brown wool, and the top of the wool block would be green, like a grass block. There would also be a 3 minute timer, inspired by the below comment by Animalll.