To conclude the story of the non-functioning furnace/AC fan...it was neither the blower nor the filter nor the circuit breaker nor the AC unit nor the thermostat...there is a light switch mounted on the ceiling in the basement (don't ask me why it is there, that is how it was when I bought the house). I have two interns (they work for an honorarium for a charity for which I am a Director) lodging with me until the end of September. Well, one is not a native English speaker. I am guessing he went down to do laundry and was trying to figure out where the light switch was, flipped it. When I asked him how he got the AC going the other day (I was at the farm and had left a note re: how to turn on the AC), he said that he wasn't the one who turned it on. What I didn't ask him was if he had flipped any switches in the basement! I didn't even think to check that switch! So all is good, AC is running and we all slept much better last night. All it cost me was I had to make dinner.
Thanks everyone for the responses. We did clean the blower per the instructions in the manual, so that was a good thing. That didn't fix the problem, but it needed to be done.