If you have nothing to do, I suggest trying to solve a couple of problems from the recent Kazakhstani Olympiads. I especially liked the problem set of the last National Olympiad, you can find the archive (statements, tests, and author solutions) on this website. I translated the statements to English myself, so I am sorry if you find some grammar mistakes. By the way, you can also submit your solutions right here.
Hope you'd like the problems.
P.S. You can also find archives of some other Olympiads, such as IZhO, on that website.