Crazy Neighbor

I've discovered today that I'm not the only one disturbed by the woman upstairs, who shrieks at her children at top volume (but, as far as I can tell, doesn't hit them) and, according to the guy in the next apartment, has now got every other tenant in the building angry at her for sitting for three and four hours at a time yelling into a phone, chain-smoking, and, just possibly, drinking. She seems to leave the kids in the apartment and use the stairwell as her personal space. The guy next door is trying to study for exams, and I'm trying to write.

Neither one of us knows what options we have, but there must be something. She's not abusing the kids, just disturbing the whole building. The rental agency doesn't care, I'm sure. Does anyone know what options we have?