GPSs and Dates
Turned on my GPS yesterday and let it try and sync up to some satellites but it couldn't find ANY. I was starting to think my GPS was hosed up, it was really weird. After looking around for a while I found the date on the unit was wrong (it didn't have batteries for a week). After I fixed that all the satellites popped right up. It must look for the satellites in certains parts of the sky based on date. Weird.