Greg,

I am having the same problem with my YellowTop Optima. I have not started the truck since my trip to Attica in October. I went to start it today and nothing. I jumped it with my Dodge and the truck started and ran. If I took the jumper cables off the Toyota, the truck started to stumble, flashed the check engine light, and died.
I am going to get a battery charger and charge the battery in the garage where it is warmer than 10 degrees and see if this helps. If not, I am going to buy a new battery and return the old one on the new receipt, because I do not have the receipt for the old battery.
Oh, and my battery is almost brand new. I just bought it in July before Bloomsburg.
I have never had a problem like this before, but then again, I have never let my truck sit for 3 months in below freezing tempuraters without starting it every now and then. I guess I learned my lesson. Just start the truck every couple of weeks to keep things fresh.