It happens to the best of us: a busy day combines with a brief brain lapse, and suddenly, you’ve double-booked yourself. It’s a tricky situation for anyone, but when you’re one of the world’s most popular concert pianists, it’s a major headache. Enter Garrick Ohlsson, who is scheduled to appear in both Newark and Montclair, New Jersey, this coming Friday night. Unfortunately, cancellation was not an option for either concert; fortunately, the two towns are only 12 miles apart. The solution: Montclair’s concert will be pushed up by half and hour, and as soon as he is done taking his bows, Ohlsson will dash off to Newark, arriving minutes before he is scheduled to take the stage.