This is a young adult novel I read within the last 5 years, but I can't say it was new at the time.
(what I remember) Near future. The main character is a high-school boy. There is a new computer game. But you cannot buy it. Someone gives you a disk with the game copied onto it. But you have to agree to conditions: you will play only in private; you will not reveal outside the game anything that happens inside the game... After you play a while, the game starts to ask you do perform some seemingly meaningless tasks in the real world. Most of the time we, the readers, are trying to figure out what is going on: is there something sinister behind this game?
Obviously I remember this book. But I do not remember the title. What is it?