A complicated question, on some levels.
Imperatriz’ samba enredo has been voted the most popular of the Grupo Especial songs for Rio Carnival by a specially selected panel of judges in O Dia, the Rio de Janeiro newspaper. I agree; nice melody, good lyrics and, crucially, easy to sing.
Imperatriz’s theme for carnival 2010 is ‘Brazil of all the gods', and you can see a preview of their costumes for carnival 2010 here. Imperatriz’s carnavalesco (artistic designer) is Max Lopez. The official Grupo Especial CD is released on 7th December; you can buy it here.
The pagode do Trem - a samba party till dawn in Rio, involving four sound stages, many samba stars, song, dance, beer, and four trains. Now this is an event that I would REALLY like to experience...
Celebrating the Brazilian Day of Samba on Dec 2nd, the event starts with a live stage set up in Rio's central rain station. From 12pm there's a big samba da roda in the station, with many samba stars performing - including (in 2009) the velha guardas of Mangueira and Portela.
Then, from 7pm, four trains set off towards Oswaldo Cruz. These party (pagode) trains contain a mixture of normal passengers, drums, music, songs and samba stars of the calibre of Nelson Sargento and Dona Ivone Lara. Everyone disembarks at Oswaldo Cruz, where there are three more music stages and a party that goes on till dawn.
Tickets are going on sale in the next couple of weeks. They will all be sold out in minutes, mostly to Cariocas (Rio locals) and agencies. As a tourist you are very unlikely to buy at these original face prices. Expect to buy from an agency with a mark-up of at least three times the face value. Its already possible to reserve tickets for the sambodromo through online agencies.
Original face values:( R$ = Brazilian Reals);Frisas (for 6 people) from R$3000 to R$6,500 per night, Arquibancadas (stands or bleachers)- from R$110 to R$300 per night per seat.
I've heard a sneak preview of the Rio carnival official samba CD 2010 (Grupo Especial) and it rocks! Read more here
Heres a pic of one of the costumes the samba school Mocidade Independente is producing for carnival 2010.