I like exercises that have max effect for minimum time and movement, and this is one of my favorites.
The "spinal flex" exercise from Kundalini yoga strengthens the spine, energizes the body and stimulates the thyroid gland to increase metabolism.
Sit in easy pose on the ground grabbing the ankles, or alternately on a chair holding on to your knees.
As you inhale deeply, flex the spine forward pushing your breastbone towards the ceiling, keeping the shoulders relaxed and the head straight. Imagine you are holding a book on your head. Exhale and relax the spine back curving to stretch the vertebrae slightly. Continue rhythmically with deep breaths for 1-3 minutes.
There: Friday's fitness program all done, you have a stronger spine and more energy, yay:D