Tommouse: I recently ordered a microscope for school. It was delivered via UPS yesterday. Interestingly, the tracking page indicated the package was still on it's way from San Diego about 30 min prior to the brown truck pulling up to my driveway. Just for kicks, I checked the tracking page again late last night, and, amazingly, the package had been routed from San Diego, to our local UPS station where it was scanned, to my UPS driver's truck to my front door -- all in about 5 hours' time.
I agree with Mayaman, the UPS tracking system sucks. I would venture to guess, though I haven't actually read the agreement, that this is why you must click on the little box indicating you understand the terms of the tracking system (read, "Our tracking system bites, and you won't hold us responsible for any false information you receive from it.") before you can actually track a package.
Of course, this won't stop me from checking my tracking number every 5 minutes for the next 5 days until I get my 3790.