I'm do biomedical science at university at the minute, so I could bore you with genetics (my keen interest) or some microbiology, and there's some facts I've learned whilst studying, that still blow my mind to this day and I tell everybody that I can. So I want to show that genetics is mind-blowing;
You (humans) have an average of 30,000 genes in your genome, and even if each one had just two variants, there is a combination of 2 to the power of 30,000, which is a big number. And each nucleated human cell in your body has 2.24m of DNA in each tiny cell, but is compressed to a microscopic size (6 micrometers avg), and if you took all the cells in the human body (3.72 x 10^13 according to recent studies), and multiplied it by 2.24m, you get 8.3328x10^10km worth of DNA, which can fit around the Earth 6539632.7 times; Just one person. I did all the boring maths, so you don't have to
Hope it blows your mind and I hope I've I've taught you something new.