In cash games, maniacs are pretty easy to beat. Since the blinds stay the same, you can simply wait for an ideal situation to occur, and get your money in when it is sure to be good. In tournaments, it is not nearly as easy to do this. There is much more pressure to accumulate chips, and we cannot afford to wait for an ideal situation.
So what can we do? Against an all-in, I think we should be looking to widen our range from the blinds. The reason we should do this from the blinds and not from earlier positions is that the players still yet to act could wake up with a hand that can crush your marginal hand. If we're in the blinds, we are usually going to go heads-up with the villain, so we can call without fearing a multi-way pot.
Sometimes the maniac will get lucky, and that's just the way it is. But poker is about making the right decisions, and if we can catch our villain running wild, we should be very proud of ourselves, even if we don't win.