Fun with Geometric Progression

I have been enthralled with this puzzle recently:
Imagine you have a paper large enough, and capable of being folded in half 50 times. How thick will it be?

Most people imagine in folding paper in their minds eye. Common answers are as thick as a phone book. However, if you do the math, you get a much different answer. 1x2^50 is the answer. By the time you fold it 20 times, you will have thickness equivellent to 2 million Harry Potter books, or around 200 miles. By the time you get to 50, you have met the distance from the earth to the sun.