Citizens of some countries (click to see list) do not require a visa to visit Brazil for strictly tourism purposes, provided the stay does not exceed 90 days.
Tourist trips to Brazil includes visit to relatives and or friends, unpaid participation in athletic or artistic events, competitions and unpaid participation in a scientific/academic seminar or conference sponsored by a research or academic institution.

Requirements:

1. Each traveler must complete their own Visa Application Form
(https://scedv.serpro.gov.br/frscedv/index.jsp), including children under 18.

2. Payment of a fee, which varies according to the type of visa and length of stay.

3. Passport must be valid for at least six months from the date of the visa application.

4. Recent 3x4cm or 5x7cm photo on white background.

5. Children under 18 unaccompanied by parents or guardians must bear an authorization form signed by both parents.


Visa information and pratical tips can be seen in
http://www.visitbrasil.com/visitbrasil/opencms/portalembratur/en/dicas-praticas.html

Entrance Visas in Brazil:
http://www.portalconsular.mre.gov.br/estrangeiros/qgrv-simples-ing-09.01.2014.pdf

More information can be obtained from the official website of the Brazilian Government
http://www2.brasil.gov.br/para/visit-and-live/visa