Balance poses, in general, offer a calming effect on the body because of the focus (or drishti) that is needed. In order to maintain your balance, the recommendations are to focus on a non-moving, eye-level (or above) spot, and to breathe steadily. In my opinion, Tree Pose (vrik-SHAHS-anna) is a great pose to start with because of the options for modifying which develop balance and concentration. As the different variations are explored, legs and feet are strengthened providing increased flexibility in the hips. Exploring arm placement can lead to an opening of the chest and toning of the shoulder muscles. I like to practice this while doing the dishes or brushing my teeth at night, in addition to incorporating it into my regular practice.