Hakini Mudra
This is a very interesting and significant Mudra that can be practised anywhere, at any time. Unwittingly, this Mudra is quite popular, since it is good for the brain.

People should sit down in contemplation with both hands in front and the fingers touching at the tips as though in deep thought. The fingertips of both hands should be placed together. The eyes should be directed upward with the tip of the tongue placed on the gums while inhaling. Make the tongue fall again while exhaling and then take a deep breath. This helps memory.