For nine days in late October or early November, Thais of Chinese descent will change their ordinary diets and eat only vegetarian meals. Many restaurants will offer special menus during this time, and there are many street stalls that only exist during the festival.
The foods on offer are far from dull. They can in fact be quite delicious. Some eateries specialize in reproducing the taste of popular Thai foods using only vegetables. It's quite easy to find the well known hot and spicy Tom Yam Kung soup made entirely from vegetarian ingredients, replete with small vegetarian 'shrimp'. While such curiosities are interesting, they're by no means the only dishes on offer. There's an amazing variety of dishes on offer.
Places offering vegetarian fare during the festival will generally sport yellow flags or pennants with red Chinese letters on them. Full service restaurants will usually offer vegetarian dishes in addition to their normal menu. Street stalls sporting the flags will generally sell only vegetarian items.
The festival is based on the idea that every year, at the beginning of the ninth lunar month, our ancestors are allowed to leave heaven to come to earth and check up on their descendants. Our lives are supposed to be lived in tribute to our ancestors. Our behaviour determines how they will be reborn in their next life. So, we want to be on our best behaviour when they come to visit.
Since 'good' Buddhists are supposed to be vegetarians, being on your best behaviour means being a vegetarian, at least when the ancestors are looking. The whole idea has something of the air of 'covering your behind' -- like the kid who's only good after Thanksgiving. We want our ancestors to know that they can't blame us if they come back as a slug.
However, people do take it seriously. One Thai Chinese friend told us that his family has separate sets of cooking utensils for the festival, to insure that everything that touches the food is 'untainted' by contact with meat.
Phuket Vegetarian Festival
The extreme version of the festival as it's celebrated in Phuket has its origins in the mid-nineteenth century. The exact details vary, but the common elements are a disease which made most of the Chinese community sick. Realizing they had been neglecting their duties to their ancestors, the Chinese performed their rites -- with extreme prejudice you might say -- and almost everyone recovered. Since then these acts of self mutilation reminiscent of the Hindu Thaipusam festival have been performed every year during the regular Vegetarian Festival.