I saw "Dawn of the Dead" a couple of nights ago. In the movie, a small group of people have locked themselves inside a shopping mall to escape a very large crowd of canibalistic zombies, that soon surround the mall. After several days of being stuck in the mall, the small group of people find their way to the roof, where they pass the time picking off zombies, that look like celebrities, with a rifle.
"Hey, get the one that looks like Rosie O'Donnell!"
"Naw, too easy of a target"
Burt Reynolds!
You must be talking about the remake since I have only seen the original and Rosie was unknown in those days.