Impossible Dreams by Tim Pratt is one of my favorite short stories ever. I re-read it recently as part of the Other Worlds Than These anthology (which I'll be reviewing soon) and enjoyed it immensely once again.
But I'm far from being the only one that loves this marvelous story. In 2007 it won the Hugo Award and the Asimov's Readers' Award. And now (well, in fact in 2011) Shir Comay has made an awesome short film based on it. The movie is on hebrew, but now you can watch it online with English subtitles.
I highly recommend this excellent film adaptation of a wonderful love story about movies and parallel universes. Just press play and enjoy!