Besides being a popular feast, Carnival in Rio is a show business; people having fun are just part of the business. Most events in Rio's Carnival happen either in ball-rooms or in the Sambodrome.
Since a few weeks before the official start of Carnival, several clubs promote pre-Carnival balls. These balls happen both in big clubs (like world famous Flamengo) or smaller suburban clubs. Almost always, one must pay to party. The price of the ticket depends on the organizer.
As Carnival approaches, these balls pop up all around the city. Many are suitable for entire families; some are even dedicated to children. Most balls, however, start after 11 pm and are adult oriented. The most famous of such balls is the Gala Gay. The most famous balls are frequented by tourists, nationals and foreigners, and the organization, as well as the government, have a special interest in keeping these events safe.
The Parades at the Sambodrome:
This is for sure the most known Carnival event of the world and to some people the greatest show on earth.
Sambodromo is the name of the domus built for the parades of Carnival (under the structure of the Sambodrome, there are schools which attend children the rest of the year). Like a football stadium, the audience must pay to enter, and the prices, which vary according to the location of the seat, may be expensive; going to the Sambodrome usually takes much savings effort for the average Brazilian salary-people.
During 2 nights, 14 Samba schools (the collective of people is designated as a "school") parade along the Sambodrome; 7 schools perform the Saturday; the other 7 come on Sunday. Official judges analyze the performance of each school under several criteria (rhythm, cohesion, costumes, timing, audience response, etc), a grade (from 0 to 10) is given, and the school with more points is the winner.
Every carioca loves a soccer team; likewise, every carioca loves a Samba school.
The work to be the best school next year starts as soon as the last parade is finished. Most of the hard work is done by humble people who save their last pennies to have a nice costume. The song theme is composed months before the parade, and countless rehearsals must be attended by the school members (the rehearsals take place during nights and weekends).
The votes of the judges are tallied up in the presence of the school members, and the quarrels about biased votes are inevitable. Seeing their school being the champion is, for some people, comparable to seeing Brazil winning the World Cup.
Even though it's the efforts of these humble people that the school depends on, business sense opened space to qualified strangers. Famous artists (particularly beautiful women) are invited to join schools, in an attempt to captivate the masses. Also, one may buy a place in certain less ostensive groups of the school; knowing how to Samba is not a requisite, foreigners are welcome.
There's much more to Carnival than the Samba Parade, though. Street Carnival is loads of fun, free, and it happens all over the city. You are more than welcome to watch and to participate.
Banda de Ipanema is one of the most traditional ones. It was founded in 1964, and today it's listed as part of the city cultural heritage, attracting as many as 15,000 people.