Stratego, a classic. Also try the 4 player version. It is just as good, if not better.
One of the best strategies is to have a bomb in the square in front of the corner, where most people put their flag.
bomb–->>>| *
corner–>>>L_
So they hit the bomb, and they know your flag is the next spot. put a number 4 in that corner spot where they think the flag is. (The sergeant, the unit ranking one higher than miner.) The rules say that when any unit hits a bomb, the unit dies, and the BOMB STAYS. Some dippys play that the bomb is removed, which is stupid because then there is no point to a bomber! Tell me if the diagram is confusing because it probably is.