This is a practice from my book Leap Before You Look.

Lie down on your back
Under a cloudless sky.
Open yourself to the nature of infinity.
Let yourself move out infinitely in any direction
And be soberly present with the unavoidable fact
That as far as you travel,
You are still only halfway there.
There are no limits.
You cannot think about infinity.
It will blow your mind.
You can only become one with the infinite.
Look into the sky without blinking.
Let the sky enter you, so there is no inner and outer remaining.
Then close your eyes and stare into the inner limitless sky.

This simple practice, to look into the open, cloudless sky, has been used in every tradition in every age. I was introduced to it in the Tibetan refugee community of Bodh Nath in Katmandhu by the great Dzogchen teacher Choki Nyima Rimpoche. Once it is pointed out to you, it becomes so obvious—it was there all along. Many of us get involved in spiritual practices and teachings, searching for who we really are, and the answer is right there above our heads all along: you only have to look up into the vastness of the sky. This practice is great for modern humanity, as we have grown so used to a man-made world. Everything has been modified; everything has our fingerprints all over it, except the sky. The vastness of the sky cannot be touched, cannot be modified; it remains the last outpost of absolute innocence. (more…)