So my identical twin brother had a homework assignment from his Creative Thinking class in grad school (he was studying Marketing/Advertising). The assignment was to become an "expert" on a subject you are not familiar/experienced with over the weekend and present what you know to the class on Monday.
That Monday I just happened to be driving through his town. He asked me if I could help him present his homework assignment to his class. I was skeptical at first (I just graduated undergrad and was tired of school), but after hearing his idea I couldn't resist.
His class was first thing Monday morning. In the back of the classroom there was this small lobby area for people's coats and what not. My role was to wait there unseen by his teacher and classmates until it was his time to present and I was given my cue. After about 20 minutes of waiting and listening to other students present their work, it was finally his turn.
He stands in front of the class and tells everyone that over the weekend he became an expert on TIME TRAVEL. He goes on to tell the class that he has come up with a theory and invention that will make time travel possible. He says, "Allow me to explain with this diagram..." and turns to the chalk board. That's my cue.
I burst into the room, "STOP THE PRESENTATION! STOP THE PRESENTATION!" The class is silent, confused and somewhat alarmed. "What? Why? Who are you?", my 'surprised' brother asks. "It's me! You! I'm YOU from the future! Your invention works! It really works! But you have to go home immediately and turn off the gas to your stove! I'll explain more later, but hurry you don't have much time!", I exclaim and I run out of the room.
My brother turns and tells the teacher he's sorry but he has to cut his presentation short and leave the class to check on his apartment. The teacher lifts up his finger and is about to object...but instead smiles and says, "Well done". He got an A.