What's the most stupid/elaborate/bizarre/ridiculous lie you've ever made someone else believe?

I thought it would be an interesting topic, seeing as there are so many interesting people here. I've got a hunch that many of you guys are quite devious as well as intelligent. That combination is pretty conducive to stories like these. I've got a few:

When my 7th grade English teacher went on a holiday, I made his substitute believe that I had just migrated from China and could only speak very limited English. In the classes, he would take a bit of time to teach me individually the stuff you learn in 1st grade. He didn't catch on for the three days he had us. It was hilarious at the time, but I kinda felt sorry for him afterwards.

Two years ago I billeted (let someone stay in my house) an exchange student from America. Got her to believe that I was a Mongol, and that I was hunting wolves with bows and arrows when I was 8. Was a bit awkward when she brought it up when introducing me to her friends.

My ex-girlfriend still thinks that she ran around naked and screaming at a house party this New Years. No context required.

Let's see, I made my parents believe my closet was possessed once. I am not joking.

I told my girlfriend her negative opinions on fascism, were cool, for 7 months.

I once told people I was full Asian, I'm not.

I originaly posted this on matts accusation thread but this seems like the perfect place to post it. I hope you can all forgive me.

You're not a pineapple? How could you desive us so?

I told my friend if he'd stick his tongue out and close his eyes very close to "that girl's" (whos name will not be written) face, she would kiss him. This was when I was in Elementary school. But I still remember laughing so hard when he got slapped, that I stopped making sound and liquids were shooting out of my eyes for a little while.

I found that pretty stupid and ridiculous.