Well, I'm not 100% sure why this happened, but our switch was turned off last night. When I asked them to check on it, my data center support staff tells me that the power cord to the switch was loose and therefore the power to it was off.
So my server was sitting there alive and well but the switch (which connects it to the internet) was off for about 7 hours.
Needless to say, I am very unhappy about it. I don't know how the power cord got loose because nobody should have been in the cabinet.
Anyway, whatever caused it, the power is plugged back in and all is well, and I'm hoping that this was just a strange fluke.