Rio de Janeiro is cleaning up its streets one phone call at a time. All you have to do is call 1RIO (or 1746).
This number is for all kinds of emergencies. If you see a hole in the sidewalk, you dial it. If you see a flooded street you call it. Murder, mayhem, looting, damage, and/or destruction are all reasons to call.
When not to call should also be addressed. The woman who should not be wearing that tiny bikini, at least you think she is wearing a bikini, is not a reason to call. The couple arguing on the street or the vendor who charges Gringos R$2 more than Cariocas are not reasons to call. Hell, short of a sink hole, I wouldn't even bother.
And for those who really like to inform the city of Rio de Janeiro of all their issues, get the iphone app. Oh yes, Rio de Janeiro is all 2011 that way! You take a picture of the issue on your iphone and send it straight in.
Personally, I wonder how this service really runs. They must get about 3 million calls a day. Hell, I'm sure half of them are about the huge freaking hole in the deck on Aterro where the kids play (that drops 5 feet down into sewage water or at least that is what it smells like). Either they have a ton of people answering phones/emails and are being quite efficient or there is one secretary who takes about 27 cigarette breaks and doesn't know how to check the emails anyway.
Regardless, things manage to get done here eventually. Of course by the time they are done 300 other things have popped up. Then again, to be really fair to this beautiful city, same thing happens in my tiny apartment! I can hardly keep on top of crap in 130 meters, imagine an entire city.