There are a lot but some of my HOTTEST are the Barracks Glory Hole series.  There are 9 of them and one spin off that I forget the name of.  They are SO hot with the regular military looking guys in them, one after another come into the barracks lockerroom shower and toilets.
I only wish someone would pick up where 9 left off.  They must be extreamly cheap to make and those seemed to go over well.  I think someone might have a gold mind in them.  I don't subscribe to porn websites but if someone continued this, I would be very tempted.