In the movie K-PAX the character talks about his planet where there are two suns and he say that they only rise together once in many years. Wouldn't it be impossible to have one rising and the other setting? I mean was not expected to have the two always together?
Let's assume that the planet only orbits one of the stars. Say at an earth-like distance. The other star might be where Jupiter is. In this case, each year the two suns would rise together for a few months, then straddle the planet for another period of months.
It would be very hard for it to only happen ONCE in many years. Although I guess it would depend what you mean by "Rise Together." If you mean that they rise super-imposed on each other, then this would be highly likely.
It would be the same chance that Jupiter would be behind the Sun on a given day during sunrise. If the two suns weren't on the same (apparent) orbital plane, then only once in a great while would you get a sun-to-sun eclipse. A sun-to-sun eclipse at dawn could be what he means by "Rise Together."
In practice binary star systems can have the stars very widely spaced. After all we can distinguish many binary stars optically from Earth, with even a small telescope. So the most likely situation is that the planet orbits one star, while that star (with the planet) orbits around the other.
Aldiss' Helliconia trilogy is set on such a star system. The planet in that case orbits a relatively cool red star, which in turn orbits a much hotter star over a period of several hundred years: as the distance from the hotter star varies so the climate of the planet of Helliconia varies enormously.
Clearly there will be periods of time in this case where both stars rise together (the further star is "behind" the nearer) and periods of time when only one star is seen at a time (the planet is between the two stars).