I don't see the point either .. Went to only one during my time as a student and it was just filthy.
The only upside was the womens' wet t-shirt and watching 5' to 6' people panic in the foam because they couldn't see. Downside is, your feet are wet, your clothes are dirty and every time you light up a cigarette someone throws a handful of foam in your face. The same funny people make it a point to throw some in your beer as well.
Maybe it's only fun if you're younger than 20.