movie about the sun burning out = Sunshine.

That was a really well-done movie, too. The special effects were fantastic, and the entire thing was just...eerily beautiful. And of course, Cillian.

The only other stuff I know he's in are The Wind that Shakes the Barley (Irish film) and Breakfast On Pluto, where he plays a transvestite. But I think he has some more movies coming up. :D