The eldest is having her first sleepover, and an argument was in full swing that needed some intercession:

R: Nicci, how many hours are there in a day ?
Nicci: 24
R: See ! I told you ! Hahahahahahaha!
C: No. But. You. But…
R: You said there were 30 !
C: Yes, but I was including the night

Hmm, maybe Ray Bradbury was right, and we do have Martians amongst us already…