Hi menion,
I learned that you do not want the app to do to much things automatically ;) , but what about switching to night mode automatically?
I tested the navigation feature on some longer car rides - cool feature, works perfectly! But I can't switch to night mode while driving, an automatic switch would be fine here.
There are lot's of sources in the web dealing with computing sunrise/sunset times, maybe this one could be used online:
http://www.earthtools.org/webservices.htm (http://www.earthtools.org/webservices.htm)
They offer a web service which returns an xml with some useful inormation:
http://www.earthtools.org/sun/ (http://www.earthtools.org/sun/)<latitude>/<longitude>/<day>/<month>/<timezone>/<dst>
Regards,
Elmar / mambofive.
hehe, nice idea ... added