Very good suggestions - I suppose I never stopped to think about it, but I'm already doing those things. I've found "Oh shoot, I just remembered I need to be someplace else" works really well, especially if it's followed by immediately grabbing stuff and leaving. They don't remember, and if you're fast enough, it doesn't give them time to react. It's not really a lie. Usually by the time I pull that out of the bag o' coping tricks, I really do NEED to be someplace else - anywhere but there.
I find myself looking forward to January starting in about October.