I used to use duct tape just like everybody else. Ok, maybe a wee bit more than everybody else, but still just to fix things. Then I was given a copy of Ductigami: The Art of the Tape by Joe Wilson. You should buy/borrow/steal this book. I will not duplicate the projects in the book here.
A note about measurements. I use imperial for my projects. I have converted to metric. I would be interested in any conversion errors. I am behind metric every inch of the way!
"You want to make it two inches - or, if you're working in centimeters, make sure it's enough centimeters for two inches." - Red Green
Before you can create any of these projects, you must know how to create a "sheet".
Next links.