Spiti is one of the most sought after destinations in India. Just like Mcleodganj, it's another one of the Indian Destinations which would give you a tibetan touch.
The dispersed villages in the vast lands of the trans-himalayan region shine in the shadows of the monasteries.
There are two ways of returning back from Spiti either return from the same Manali route or take the road to Shimla going through magnificient Kinnaur. This blog talks about the later one.