Anything involving black holes. Sci-Fi have made them out as planet munching monsters that go around the universe eating stuff up. Also that they're some sort of rip in space-time.
If our sun was to turn into a black hole (It wouldn't, but follow me on this...) we would orbit in the same way we do now. We'd all die from the cold of space, but we'd still orbit it. It wouldn't suck in the solar system because IT HAS THE SAME MASS AS THE SUN. Gravity is caused by mass, and you can't create mass, so a black hole is only as heavy and powerful in terms of gravity as the star (Or core of the star...) it came from! And they aren't rips in space or whatever badly written TV shows have you believe. The event horizon, the black part you see (Or don't see, whatever way you look at it...) is just the radius at which the gravity is so strong light can't escape. It isn't a surface, but it definitely isn't some sort of inter-dimensional rift.
Also, that they 'eat up' time. No, time (Like energy and matter...) can't be destroyed or cast into some sort of void, it's just that according to the laws of general relativity the singularity at the center of the black hole has a gravity so strong that time essentially stops at that point. If you were somehow magically unaffected by gravity and you were somehow magically inside a singularity, if you somehow magically managed to GET OUT of the singularity, you'd be an infinite number of years into the future. Considering the universe itself is finite, you can understand the impossibility of exiting a singularity or even the radius at which light can't get out of a black hole.