Carnival, or Carnaval, in Rio de Janeiro is when the prices treble, every hotel in town is full to bursting point and then the tourists fly in by the plane load in search of the Brazilian dream.
It's also when all the low life, criminals and prostitutes rub their hands together as they get ready to rip off all the naive gringos who fly in looking for endless parties followed by quick sex. Spare a thought for all those who end up going home a week later in tears.
Carnival in Rio itself has its roots in the favelas whose samba schools produced such excellant performances that it eventually caught on as the pride of the city. What started out as a grass roots phenomenon is now one of the most amazing shows in earth and is one of the biggest tourist draws on the planet. It's pretty sad that no one from the favelas can afford to go and see the show for themselves these days though. That's show biz for you. Or consumer travel, anyhow.
Tickets for the Sambadrome carnival processions sell out within hours and are quickly on sale for twice their price from street scalpers. Expect to pay upwards of $100 for a decent seat. Either way, it's well worth the money and jsut because everyone talks about seats, don't expect anyone to actually sit down - everyone's on their feet as the parade comes through and pools of saliva form where the sama queens pass.
The Rio carnival is largely celebrated with balls and street parties. The former are also pretty expensive but rumour has it they can degenerate into sex fests in some corners of the venue. So you'll probably want to stay away from those...
Not all the Brazilians are all that passionate about the Rio Carnival, preferring to party in other parts of Brazil or just hide on Ilha Grande until all the madness has passed.