A penny saved...

Today a grocery store clerk owed me a penny in change. "Which would you rather have," she asked me, "$10,000 today (not that she was offering), or a penny today, two cents tomorrow and so forth, doubling every day for the rest of your life?" I quickly said I'd go for the pennies. But is there enough copper in the world, or space to put it? Of course not. After a month or two, humanity would be crushed under avalanches of Honest Abe. And forget about inflation. There wouldn't be anything left to buy, because it would all be smothered in coins.

I'd get:
Day 1:  $0.01
Day 2:    0.02
Day 3:    0.04
Day 4:    0.08
Day 5:    0.16

Day 6:    0.32

Day 7:    0.64

Day 8:    1.28

Day 9:    2.56

Day 10:   5.12
Looks like chump change, huh?
But it gets better:
Day 20:  5242.88 (and don't forget we're accumulating the previous days, if we don't spend it)
Day 30: $5,368,709.12
Day 31 my calculator can't handle without using exponents. In a few days, we're zooming past Bill Gates and Carlos Slim. By two months we'll be storing extra coins on a distant moon--and probably not our own moon, which would be already full.