I just discovered that my government makes and distributes fairly durable paper wallets suitable for use with Bitcoin. Here's how to use them.
First, select three of their paper tokens randomly:
Then, type in their unique serial numbers, concatenated together with a period in between, as the passphrase of a "brain wallet" on bitaddress.org or brainwallet.org. These ones yield the bitcoin address 1M9kzNAURtUijDX9yPGh5UAmcEHvWT79VJ.
To ensure that your bitcoin private key contains sufficient entropy do not use new notes that just came from the bank. Instead select three different notes that you got as change from three different purchases. Then staple them together with a note that reminds you that these are not just some random bits of fiat.