Calculating the sunrise/sunset time for the current location.

COOL. That's a nifty idea for GPS software I hadn't thought of yet. I can think of a lot of uses for this. For instance, I have a friend who follows a religious tradition of fasting during the daylight hours on certain days of the year. For him, the exact moments of sunset and sunrise become rather critical.

What other neat things can we do with a GPS that aren't necessarily obvious right off the bat? Here's what I've seen so far:

- Automatically set the player's time clock and time zone, and keep them accurate.

- Calculate sunrise/sunset as described above.

- Use a database to warn when you're near a fixed speed-camera trap or other similar civil-revenue-generator.

Anyone else have any ideas? Sitting here thinking about it, I imagined another one: Astronomy. Calculate what planets and constellations would normally be visible from your current location and time, and list them with directions to locate them. Dunno if the empeg screen is large enough for an actual full-sky display, though. It'd have to be just a sliver of the sky that you could scroll.

Ooo, would make a cool visual, though... have the display be an accurate picture of the horizon, based on location and heading. For instance, if the moon is setting on the horizon with Venus next to it, you'll see that on the empeg screen if you happen to be driving west. And then it could have symbols up on the screen telling you what you're seeing.