There are many things that foreigners will find of interest about the Costarrican. As many countries in Latin America, Catholicism is the main religious influence.
As August approaches, people from all over the country start a pilgrimage to the Sanctuary of Nuestra Señora de Los Angeles (Our Lady of The Angels), in the city of Cartago, the old colonial Capital of the country. The tradition states that people should walk to the Sanctuary arriving there before August 2nd, when the festivities of Our Lady of The Angels takes place.
Since its relatively easy to go there from San José (the Capital), most people start their pilgrimage in the Metropolitan areas, although some, walk for days from the fartest corners of the country. Those who start the pilgrimage on August 1ts, usually start it late at night which makes driving around San José after six a moslty difficult task.
Costa Rica has a great variety of foods, it combines many different cultural influences and of course each region has developed its own culinary tradition according to the ingredients that are available.
The traditional breakfast consists of a meal called "Gallo pinto" which is made of rice and beans fried together with spices. The traditional breakfast includes a cup of coffee and tortillas. Some people also eat either Cheese or "Natilla" which is like what the French call Creme Fraiche.
The most typical meal served for lunch is often called "Casado", it consists of a plate served with rice, beans, salad and tortillas with either eggs cooked in different ways, or fish, or meat or even pork. Casados usually have fried sweet plantains.
Desserts usually consists of a fruit or some home made pastries, one of my favorite desserts is a fruit pudding made of orange and fruit juice (usually lemon or pineapple juice) cooked with cornstarch and sugar, then the pudding is placed into the halves of orange skin, giving them the appearance of the orange, some people make this pudding with chopped fruit bits as well.
Fruits are very important in the Costarrican diet, think of all the tropical fruits you've seen or heard about and probably all of them and many more are all produced in Costa Rica, so the diet also contains a lot of fruit, some of them, like mangos are seasonal, you'll find the best mangos in the late weeks or march or in late summer time, the best place to find mangos is near the Alajuela region.
Other regions like the southern regions produce excellent varieties of Pineapples and Oranges, which are also produced in the dry regions of the North. Coconuts are produced near both coastal regions of Limón and Puntarenas.
Coffee is also a very important part of the Costarrican diet and culture, since Costa Rica is one of the World's most important Coffee producers. You'll be offered coffee all the time when you visit Costarrican houses. Usually that cup of coffee comes with cookies or other pastries.
Costarrican are not usually vegetarian, but in late years a lot of vegetarian restaurants have opened giving the public great service, also there is no problem at trying to find vegetarian products at supermarkets in the central areas, this will be a problem when you go to other places, usually farway from the big cities, since vegetarianism isn't very common.