Make sure you read Stupid OPPD (part 0001) for the exciting beginning of this tale.
OPPD showed up in a little over 2 hours from when I first called. The technician had a troubleshooting device, and we quickly found no power at the AC unit. Went inside, took the cover off the circuit breaker panel, and discovered power on the input, no power on the output of the AC circuit breaker. $11.99 + tax and a trip to Ace Hardware later, and my air conditioning is working like a champ.
What caused the circuit breaker to give up the ghost at that particular time is unknown, but we'll just let that go, and enjoy some lower humidity and temperature.
Even though I would have figured it out once I borrowed a meter from Troy, I do want to say: thank you OPPD.