Ulitmate Balance Test
At the statistics screen (The screen after you choose your mii), there is the balance board character running on a treadmill in the background. Click him with your pointer and you will be asked if you would like to participate in the ultimate balance test

Alternate Jogging Routes
When jogging, occasionally a dog will run past you and your trainer. Quickly sprint past the trainer and you will follow the dog instead, taking you on a different route around the island.