I'm trying to decide which of the hobbies/activities I should take up next as a self-improvement project:
1) Fast Math - learn how to do basic math calculations fast in my head
2) Memorization - learn techniques to memorize stuff, like large lists, people's names, numbers, etc.
3) Meditation - learn basic meditation techniques to help control stress and calm the body
4) Qigong - a slow-moving, gentle martial art kind of like Tai Chi, to help maintain flexibility and health
I like aspects of each one, so I'm having trouble deciding which to pursue.
Which one would you do? Why?