Birthday parties here are events. They're not just for kids - the whole family is implicitly invited when a child gets an invitation. (One time I tried to invite JUST the kids - it didn't work.)
There are always themes - usually a cartoon character or something (Cars, Cinderella, and Spiderman seem very popular.) Everything is coordinated - from the invites to the party hats to the cake to the decorations. There are lots of balloons and usually rented wall hangings made out of styrofoam with the character glued on top.
The party lasts for hours - often into the night. Everyone hangs out, talking and laughing and eating lots of fried "salgadinhos." And, of course, dancing. It's a BRAZILIAN party, remember? These people can dance.
They hardly ever have any games or organized activities - it's just free-for-all fun. The cake is only cut at the very end. (And don't try to leave early. You'll only hear, "No no! We're about to cut the cake! Stay, stay ...." Three hours later, you're still there.)
Lots of sugar, lots of people, lots of dancing - can you get much better?