1. Killing animals is the main taboo of Tibetan customs. Even though they like to eat muttons and yar meat, they never kill by themselves.
2. The donkey, horse and dog are protected by Tibetans. In some area of Tibet, people do not eat fish, either.
3. You'd better not clap or spit on one's back, which the behaviors are Tibetans' taboos.
4. The wheels are not allowed to turn anticlockwise.
5. However the Tibetan kids are lovely, do not touch their head.
6. You are not allowed to touch the Buddha statues or scriptures, the bells and drums, as well as other religious stuffs in the monastery.
It is greatly celebrated on the forth month of Tibetan lunar calendar to honor the birth, enlightenment and parinirvana of Sakyamuni, the founder of Buddhism.
Doing alms giving is one of the highlights of Tibet Saga Dawa Festival, which would be appreciated on 15th of August of Tibetan lunar calendar during your Tibet Saga Dawa Festival tour. There are full of religious Tibetans along the both sides of street, chanting the scriptures, or walking around, or crawling with hands and feet on the ground to pray.
In general, Tibetans will be abstinence from meat on August 8th and 15th of Tibetan Lunar calendar.