In some cases, chess is permitted in Islam, as long as there is no gambling involved. Chess is an abstract strategy board game, an intellectual pursuit, which has been played by two opponents for centuries. The game has evolved into a competitive sport, and is even part of school curricula. Most people play chess as a hobby or as an activity in their leisure time. To deny people the opportunity to play chess means they would not have an outlet for which exercise their intelligence. It is mostly a fun game, and many people around the world enjoy it. Leaders of Islam have mentioned that bans on chess may be eased.
Anybody who thinks a game like chess is a waste of time clearly doesn't like a good game of strategy. A person needs to play games of strategy like chess so that the brain is constantly in use and is continually developing the mind. Some of the world's sharpest minds were that of the chess playing variety.
Even if you don't consider chess to be stimulating enough to not classify as a "game," chess and activities like it have an important role in a well-rounded society. Hobbies, games, and other trivial pursuits are not only crucial to mental health of the individual, but they play a major role in the cohesion and content of our society and culture.
I am strongly opposed to the opinion of grand mufti of Saudi Arabia saying that Chess is a waste of time. The game of Chess has been used for centuries as an analogy for war and war tactics throughout history. It should be taught to everyone as a classic strategy game.