I was working on celestia addons for my own setting when I noticed something I had not realized Celestia actually did. I had before noticed that if you triggered the display of Sun Direction arrows on a body in Alpha Centauri, you'd see pointers to all three stars, even Proxima*, but I had never before noticed Celestia actually do anything with that knowledge, at least not in wide binaries. Maybe it's because of the more favorable angles my recent adjustments have created, but I noticed that Celestia actually will illuminate bodies from more than one direction. It's not so easy to notice with Moon-like bodies, the dark gray color and low albedo make it hard to see, but for brighter bodies, it's quite striking.
http://johnsonm.com/Pics/Panthalassa-Night_Under_Kentauros.jpg
Ambient Light is set to None here, that not-quite-night you see is Alpha Centauri A nearly at opposition to B. I just thought that was cool. Think about what kind of phases you'd see on the moon of any of my planets in this system. What would you call it when a Half Moon had its dark half dimly illuminated by the farther sun? A double-half? For that matter, what do you call the phase on the undergrown Neptune you see above?
*Proxima would around the other stars have an apparent magnitude roughly equal to a planetoid in the outer solar system from Earth if I'm not mistaken, you'd be more likely to spot Ganymede with your naked eye, I think