Of Tonga's gargantuan feasts, the most spectacular are those marking such important events as a coronation or royal visit, which feature a whole roasted suckling pig for each of the thousands of guests. Literally tons of food are piled on long platters (polas) for these occasions, including taro, yams, cassava, breadfruit, sweet potato, fish, lobster, octopus, chicken, pork, corned beef, cooked taro leaves, and fruit.
Cooking is done in an underground oven (umu), and coconut cream is added to everything. Ota is raw fish marinated in lime juice and coconut cream. Less earthshaking feasts are put on for visitors to Tongatapu and Vava'u. Try to attend at least one.
In the main towns, the tap water is chlorinated and it won't bother you if you have a strong stomach; otherwise boil it or drink bottled water. Several visitors have reported that the tap water made them sick. Well water should be considered highly suspect, whereas rainwater collected from roofs is usually okay.
Unfortunately, beer is expensive in Tonga because it only comes in small 330-ml bottles, not the big 500-ml bottles used in most other Pacific countries.