Buddhist

Buddhist festivals are nearly always on a full moon - a good list and explanation is here. 

Buddhist Festivals are usually celebrated by some sort of offering to local monastic community, in the
Theravadin calendar the Kathina (or here) ceremony is very important.

Of all the festivals Vesak is probably the most important the day celebrates the the birth,death and
enligtenment of the Budda. It is also endorsed by the united nations- see the 2008 message here

Introduction to the Buddhist moon calendar here and here

Thai Buddhist calendar explanation

Buddhist calendar dates here

Tibetan festivals can be found here

Buddhist Rituals and Observances download here

Vast selction of festivals here