The book says,
If your idea of exercise involves moving your body and doing something else productive that pays a big dividend, then consider taking a class on how to lay tile or renovate/remodel your bathroom.
Laying tile involves many activities, including but not limited to carrying, cutting, and applying tile with special tile glue. But before you lay any tile, you may have to first remove old tile and/or cabinets, tub, toilet, and shower.
You will be bending, lifting, walking, reaching, and stretching during the process. You most certainly will be tired at the end of the day. But as you stretch out the soreness in your muscles, imagine how happy you'll be to have a brand new bathroom and to know it will add dollars to the value of your home.