Flutterby™! : Bitcoin explained

MeFi user Pertz explains Bitcoins to visiting aliens:

"Well, what we do is we take some black rocks or gas and burn it to boil water, or we flood an area and run water through a small spot, this is all so we get these magnets to turn even if they don't want to. Then we bake sand in to very intricate shapes, which also takes a lot of that fresh-squeezed magnet juice we were talking about earlier. So you put all that magnet-juice in to the sand, and you get certain numbers, and these numbers can be exchanged for food because... well as you can see the numbers are really hard to get! So we figure they must be worth a lot of food."