South America - ok, help me out with Carnaval please

This Feb will be my first visit to Carnival and only my 2nd to Rio (First one is in Jan for 2 days). I'm trying to get a good idea of all the happenings and activities that go on. I read some threads on here but they were a couple years old. I also found http://rio-carnival.net with a good bit of info on it and I'm still taking in more from that site. But, I wanted to get the take from the experienced people here. My schedule is that I get in mid-day on Saturday and leave on Wed.

I figure the parade on Sunday is a must-do thing. Should I try to buy tickets online beforehand or would it be better to find an agency and purchase them once I get there. Any recommendations on places to buy the tickets and/or reasonably priced seating locations would be appreciated. :)

What other things should I look at doing for Monday & Tuesday? Are there more parades? Other events?

Which Carnival Ball would be recommended? I'll be there with a semi-gf so not looking for a strictly singles scene. Is the Scala Ball of the Marvelous City
on Sat worth the $54pp ticket?

I am hardly an specialist, but I would recommend the following:


*Book the Sambodromo parade in advance and definitively try to stay in a "camarote" (boxes)
*There is a street parade called Cordao da Bola Preta that is surely worth participating if possible. It parades around Rio downtown since 1918 and is in my opinion the most authentic carnival experience in Rio. It is free and the parade starts early morning in the Saturday. Around half a million people participate in the parade and rarely there is an incident.

If I remember something else I will post here.

Any recommendations for sites to purchase the tickets through? Also, I'm going to be in Rio in January. Are there any places that I can go while I'm there to purchase tickets?