Question: You are standing on the porch, gravity holding you firmly down, your house is floating in outer space, and you send a gob of spit out of your mouth. What happens?
Reasonable answer: The spit falls, depending on the effort you put into it, one to three feet away from your feet, after describing a parabolic trajectory.
The Zathura answer: Your gob of spit joins the ranks of objects floating weightlessly on an infinite zero-gravity orbit.
Zathura is still a fun movie, if you overlook such defiance of physics and the whiny little younger brother. I was quite surprised at how the story was spun in such an engaging manner given the severe limitations vis-a-vis location.