Tough one since sometimes you might have just burnt yourself out on something and need to take a break from it. But occassionally when my game is crashing constantly or my save is going through a patch where ****** all is happening for months on end (which in international management happens quite a lot) then I just put on a film to watch while my game progresses, or recently a cool boxset I picked up called '50 greatest footballers'.
Football manager doesn't take a huge amount of thought or effort, and when my game reaches the next crucial thing like a big game or tournament...the excitement makes an appearance again.