The ones of the "humiliation" variety, usually to be found at some Universities or rugby clubs etc.. are a case in point, as mentioned here. The acts dreamt up out of a misplaced sense of humour, they can be more nasty than meets the eye, as in some cases people have died as a result.
But what does get me is why some people do such things. Well the BBC News story which I have linked to gives one such example:
Another, Nick Levy, said that during his ceremony he was told to drink excessively and then run naked through Cheltenham.
He added: "We had to put matches in private, inappropriate areas and set them on fire whilst drinking more beer. I did it to be accepted by the older guys at the time.
"It was a bit tormenting, but if you didn't do it you would get called a wuss".
Personally I'd rather be called a wuss. And given that in one ceremony a student died whilst choking on his own vomit, I don't see these initiation ceremonies as something to be tolerated either. I am not sure I agree with the NUS for an outright ban as I don't know if that would be workable, but I do think there should be stronger voices against such acts