Approximately 10 minutes of strength exercises.
For the mind:
Further exploration of the veritable tome, Einstein: His Life and Universe by Walter Isaacson.
For the spirit:
Twenty minutes of mindfulness meditation on my upstairs cushion. I also found an interesting meditation, "The Way of Cats", given the propensity of my cat, Zak, to want to sit when me when I meditate. It's an excerpt from Interluderetreat.com
Some people make meditation complicated. They think it must be done according to a technical prescription. The posture must be just so. The hands must be held just so. The proper mantra must be recited. The incense must be lit. All the equipment must be placed correctly. Their cats, on the other hand, meditate just fine without any instruction and in the most varied circumstances.
A cat will sit and stare at a spot on the floor or out the window and be completely transfixed. They require no preparation for this. They have total concentration, minds empty of worry or care. Nobody forces them to this contemplation. They have no superego harrying them to do their duty. Perhaps because they are predators, they have the gift of natural, relaxed, alertness and focus.
Cats have the ability to take joy in simple things. They eat. They play. They give and take affection. They do their duty of protecting the household from small moving things, because that is what they are drawn to do.
There is nothing complicated in the world of a cat. No one needs to tell them when to go to sleep, and when they awaken, they stretch their muscles in a natural yoga that no one had to teach them. When they move, cats step softly and move swiftly, or oh so slowly, as the situation requires. Their stealth is the envy of the greatest ninja. As Doris Lessing said, "If a fish is the movement of water embodied, given shape, then a cat is a diagram and pattern of subtle air."