As a random whim, I want to see if it's possible to send one satoshi to every bitcoin address that's ever been used. How much would that be? I'm betting the transaction fee would be a lot more, though. Is this even possible? How would I do it?
Yes. There are currently about 10 million unique addresses in the block chain, so 0.1 BTC would be enough to send a satoshi to each address. The transaction data would be about 340 MB. The network's anti-spam protections would make this project either very expensive (due to transaction fees) or very time-consuming.