Calories burned: 200 for an hour of standing or playing with kids. To make your meet-ups more varied, consider combining activities: make kites and then fly them outside; walk to the ballpark instead of driving; prepare a healthy feast using fresh veggies and fruit.
Muscles worked: Sky's the limit.
Karmic bonus: Your mentee gets a fresh, unbiased take and encouragement on her academic interests and career aspirations.
Next: The busy person's guide to volunteering