In New Jersey, you can unlock the School level from Tony Hawk's Pro Skater 2. Cross the bridge, then get on top of the large building immediately afterwards. Shimmy across the tall gate and pull yourself onto a ledge. It will be on the ledge alongside a tall building. Have the station area unlocked. Go to the station area and get air off the middle quarter pipe in the back. You will see a floating icon marked 'Tony Hawk 2'. Run into it and the School 2 level from Tony Hawk's Pro Skater 2 will be unlocked.