My uninterruptible power supplies were a good investment, though of course I should have had them before the August 14th blackout! The one in the living room seems to have kept the TiVo and satellite receiver running through the whole blackout, which was a little over an hour in duration. They both started beeping about once every eight seconds to tell me they were on battery power. There was no obvious button to make it stop beeping, so I sat and let it beep for a while. Sleeping was definitely not an option. Piercing beeps.
The other one, in the back room, powers two of the Macs, including the one that hosts some 14850.com and wvbr.com databases, and the cable modem and wireless router. It was fun to be online on my laptop and chat with Rachel (she seemed to be the only one awake) while there was no power.
When that one started beeping every second, I realized it was running low on juice, and went to try to shut down those computers cleanly. I got the G3 off in time, but not the G4. Then I decided I'd try turning off the UPS in the living room; powering off the TiVo wouldn't be disastrous. Turns out one push of the power/test button simply stops it from beeping! I'll have to remember that next time.