Hal: Mmm, I'm starving. What's for dinner?
Lois: Leftover parfait.
Malcolm: [to camera] It's even worse than it sounds! Once a week Mom cleans out the fridge. Anything that doesn't actually have something growing on it gets thrown in a casserole and served for dinner.
Reese: Did we have spaghetti or Chinese food on Thursday?
Dewey: Neither.
Lois: [to Hal] Ah, no digging!
Malcolm: Sunday, Saturday, Friday. It finally happened! The fifth level of this week's leftover parfait is last week's leftover parfait.