My fiancee is an RN which means she works 13 hour days. By the time she gets home she is usually really tired, by still wants to watch a movie with me. I tell her that if she isn't going to be able to get through the WHOLE movie without falling asleep on the couch then I'm not going to even start the movie.
We actually invented a term for this called "TWO PIECING" Which basically means as soon as she has the slightest sigh or feels herself falling into dreamland, we stop the movie right there and resume at that exact point the next night.
I really HATE "Two Piecing"