In fantasy games, when the PCs slay the fell beast and claim its hoard, it can be tough to conceptualize just how large that hoard actually is.
Enter The MegaPenny Project , which lets you visualize that most humble of American coins in large numbers. Very large numbers — like 50,000 pennies  (a lot of money, but not a big pile), 1,000,000 pennies  (an epic hoard, and yet still not that huge) and the economy-crushing 1,000,000,000,000,000,000 pennies  (which is ginormous).
Substitute “gold pieces” for “pennies,” assume the gold pieces are a bit larger than pennies, and you really get a sense for just how large that dragon’s hoard might be. (Via Boing Boing .)