Out of all the questions you've ever asked this has got to be the most ridiculous. Anyways an easy thing to do would be to flush lots of toliet paper until it clogs, flush again until the water rises, and depending on time and how well clogged it is, the next flush should overflow. Of course the type and size of toliet can change the situation.
But an interesting thing to do would fill the toilet bowl with lots of baking soda, until the water becomes sort of a paste. Then remove the water from the tank the water is held in before the flush, and fill it with many bottles of vinegar. And as we all know baking soda and vinegar produce a nice reaction, which should occur at the flush. It all sounds good on paper, but if it will actually work is the question.