When they get hungry at night, they start circling. Eventually they sit in front of Seth until he gets up to feed them. They did this yesterday while we were watching a movie. When the movie ended he said, "Okay guys, it must be time for you to eat, you've been pestering me long enough." He turned on the light, looked at the clocked, and realized there was still an hour and a half until their dinner-time. Stupid cats. Of course, he had to feed them anyway, because they were trying to kill him by getting under-foot.
However, Pipsqueak is very cute and pathetic. She's almost always curled up in a tight little ball on the bed (hello? duh. Why do I think I wake up sniffly and sneezy every day?). She's especially fond of the bed at night when the electric blanket is on. We hadn't been using the electric blanket, until we realized how freaking cold it's been getting in the middle of the night. Silly us.
Anyway, point is, you were all right, the cats are back to normal-ish. Pipsqueak must just have smelled like the vet's office which set off Charlie's radar. Wait til he finds out he has to go soon too. ;)