the incest version:
Mom uses her BB as alarm, but forgets to charge it. as a result, wakes up an hour later. races through the house waking up hubby 7 over 18 kids.
Dad, with morning wood, walks half awake into bathroom where 18 yr old daughter has just stripped for shower.
But mom does not respond to the scream of surprise, cause when she goes into 20 year old son's room - well, not sure if he should be beating his massibve meat, or fucking a strange young woman, but in either case, mom can't take her eyes off it.
the non-incest version:
dorm or sorority- the "adult" in charge replaces mom in the above, there is no Dad, but there is a guy who was sleeping in one of the rooms...