Sewage backup ... lovely

I was awoken early this morning by my cat and the smell of sewage. Only, I was so out of it I didn't know what the smell is; at first I thought it smelled like natural gas, but we don't have natural gas to our house at all.
I have one cat who wakes me regularly and one cat who always leaves us alone in the morning because she likes to sleep in too. But today at 7:30 a.m., the usually sleepy cat, Wylie, woke me up. Once I heard city sewer workers outside on a loudspeaker talking to each other and got up to see a carpet cleaner across the street and a big sewer truck, I realized I should go look in our basement.
Sure enough, there was standing water in the laundry room, bathroom, carpeted downstairs landing and a little bit in our office.
Either Wylie woke me up out of concern for what was going on, or she just couldn't get past the water to her litter box in the laundry room. Either way, she is a good watch cat when she's not hiding under the bed.
We've got most of it mopped up, and a carpet cleaner is on the way. It could've been a lot worse, as the drains were working again by the time we noticed the problem.
Of course, the sump pump is on the other side of the house, so it was dry as a bone. Go figure.