ten minute rule 

An urban legend holds that, if a student arrives on time for class, and the teacher does not arrive within ten minutes of the official class start time, then the student is entitled to skip that class for that day without receiving an unexcused absence. Few, if any, schools actually have such a rule; yet the myth endures because of the student appeal of such a rule.

The rule is not necessarily alleged to be ten minutes. The "five minute rule" or the "fifteen minute rule" have also been used in this same sense.

What the fuck, it's 9:08 and Kotter's not here yet! Two more minutes and I'm invoking the ten minute rule.

ten minute rule by conculcate September 7, 2005

ten minute rule 

The amount of time a DVD supplied by a through-the-post rental service has to prove itself watchable. A way of dealing with the inevitable question; "Who the hell picked that!?" when some discs arrive. A damage limitation excercise. Life is too short for bad movies.

Shyamalan's The Happening dropped through the door in the morning so we thought what the hell. We used the ten minute rule. It didn't make it.

ten minute rule by Hierophant September 6, 2009