When you are in kathmandu doing nothing, you can spend a day exploring the historic UNESCO sights in Kathmandu valley. Start early in the morning with a short hike up the Swayambhu Nath Stupa (monkey temple) would be a good option to catch up the morning valley view. where you have a commanding great view of the valley too. The stupa itself with its golden spire dates back to the 5th century and is one of the most important religious sites in the city.
Your afternoon will be in to the holy Hindu of site of Pashupatinath Temple which is really a collection of temples laid out along the Bagmati River. Sadhus or holy men can be seen in elaborate fare and cremation ceremonies along the banks of the Bagmati river are common.
Evening you you can extend your trip to the historic sites Kathmandu Durbar Square in the heart of the city which features a collection of ancient temples and you can extend your journey to Boudhananth Stupa a pilgrimage site for many Buddhist and a traditional stopping point for merchants plying the trade route between Nepal and Tibet. Its one of the most popular sites in the city and still houses hundreds of Tibetan merchantswho have set up shop a midst the prayer flags and tourists.