There are many festivals celebrated in Khumbu, but most famous is the Mani Rimdu. In Tengboche the Mani Rimdu is performed in the 9th Tibetan month which usually falls in late October. It is also performed in Thame in the 4th Tibetan month. The prayers will be said over many days but for the villages the most important part is when they receive the blessings from Rinpoche, and when the monks perform the masked Dance. After this the whole village gets together and dances until late in to the nigh. These colorful and festive celebrations are the culmination of ten days of prayers on the Buddha of compassion, Chenrezig. They are done for the benefit of all beings.

The Mani Rimdu in Tengboche is performed according to the tradition of Mindroling and came from Rongbuk Monastery north of Tengboche in Tibet. The name comes from "Mani" part of the chant of Chenrezig, and "Rilbu" which are the small red pills, which are blessed throughout the ceremony and distributed to everyone at the end.

At the beginning a beautiful and intricate mandala or sacred diagram is drawn in fine colored sand. The sand is collected from a special place high in the mountains. It takes four days to complete the mandala then it is covered and used as a focus for the next ten days meditation. The monks perform the sacred mask dances known as "Cham" There are sixteen dances with some comic interludes that delight the crowds. These dances are a recreation of the establishment of Buddhism in the Himalayas by the legendary Padmasambhava, known as Guru Rinpoche. The dances convey Buddhist teachings on many levels from the simplest truth to the most profound realization. Throughout the dances, symbolic demons are conquered, dispelled or subdued. The symbolism can be interpreted on many levels; the inner "demons" of hatred, greed and ignorance overcome through meditation on compassion and wisdom. On the last day a fire ceremony is performed by the monks to allay all the harm in the world. Afterwards the sand mandala is symbolically dismantled and the merit dedicated to the benefit of all sentient beings.