I wonder when he'll ever leave  

Yes I know what you mean I have a friend like that except every time she comes it's a new delemma story that she ends up in tears about and is going on for hours about and it drives me batty. After about 3 hours of it I make up something just to get her to leave. I know she is mad at me now for she has been calling and I ignore her calls oh well I need a break if ya know what I mean.

I had been on that situation lots of times. For the first time he or she has done that to me it was fine, but then later on he and she keeps repeating to do it, it can never be fine again. I once had a visitor they came from the next city where I am now, and I thought she is just staying for a night and so I did what I can to entertain her talking the whole night. And I end up sleepy all day, and then she still didn't leave and spent another night. That night I never talk to her again and I asked her what time is she leaving for the morning, because I am going somewhere, and now we don't communicate anymore.

Oh yes, and more frequently than I like. I do the same thing, mentioning how tired I was and it's late I have to work in the morning. A couple of yawns usually have already happened or start following. I used to wait another 15-20 minutes and have to say how tired I am again and I swear, whomever it is just doesn't seem to get the message. That's it in my book, I or my husband get up and tell the person thanks for visiting and see or talk to you in a couple of days because I will be very busy and really won't be available. I then just start doing what I would do, turn off the lights, put the dishes in the sink, when I'm ready to turn in. That usually does it the company leaves and sometimes, and it's not very often, will I not be bugged over the next 2 days. That's if they really payed attention to what I was saying that night or maybe they just choose to ignore. Either way, I'm glad I have an answering machine. I let that be my life saver a few times.