From Oxford Dictionary: Diversion: an activity that diverts the mind from tedious or serious concerns.

A few weeks ago my Principal interrupted the first period class I was filling in.
Him:  Do you have a second?
Me:  I just got started with my lesson, but...
Him:  Thanks. Would you be willing to sub for the Arabic block for grade 6?
Me:  They can come to my classroom and have a study period while I prepare for my normal classes.
Him:  No, I meant will you please teach them Arabic.
Me: ....I don't speak Arabic.
Him:  That's alright, they just need a basic lesson to fill time during Arabic. It can be impromptu.
Me: ....No. I do not know how to speak Arabic.
He reached over to touch my shoulder:  It's just for today.
I backed away from him, then using exaggerated arm movements and speaking slowly:  I. Do. Not. Speak. Arabic.
Him:  ...Huh... Really?...I thought you did.
Me:  No.
Him:  I guess I'll go ask David, I know he's pretty good with Arabic.  [He isn't]
Me:  Good idea.

Later that day 6th graders showed up in my room, so I made them sit quietly and read. The Principal poked his head in the door.
Him:  What are you doing?
Me:  Preparing for my next class.
Him:  You are supposed to be teaching Arabic.
Me: ...I don't speak Arabic.
Him:  We all face challenges, but we need to work together to reach our goals. You should be teaching these students Arabic.
Me: ...I'm sorry. It was foolish of me to think of myself in this situation and make a decision not to teach them a language I don't actually speak.
Him:  Thank you for thinking of the team. (As he turns to walk out the door he faces the students) Now, Grade Sixers, listen carefully to Mr. S because he'll be your new Arabic Teacher! Have a wonderful day!

Students turned to look at me, then looked blankly around at each other.
Student: You teach us Arabic, Mr. S?
Me:  Nope.
Student:  What we do then?
Me:  Whatever you think will annoy me the least.
Student:  We keep reading.
Me:  Good boy.