Not quite a houseguest but during my time in college dorms my roommate knew someone who would come to your dorm room to cut your hair for $12, or for $10 if you came to them. My roommate also had a friend who frequently hung out in our dorm room, he wasn't intrusive so it wasn't a big deal. That friend one day decided he wanted to get his hair cut, but for some reason his room wasn't good enough so my room was decided upon as the day's barber shop. He gets his hair cut and leaves immediately after. I had been at work this whole time so imagine my surprise when I come back to a chair in the middle of my room with hair covering the floor. My girlfriend was on the way over shortly and trying my hardest to ignore the dumbfuckery afoot I clean it up and get on with the night's plans. To top it all off at 12pm that night guess who comes knocking with broom in hand ready to clean up the hair? Suffice it to say I told him to fuck off pretty quickly after answering the door.
TL;DR: College roommate's friend decided to spend 12 dollars to have someone spread hair all over my floor for me to clean up.