Part of the Coins project.
Cryptocurrencies such as Bitcoin use a "proof of work" system to prevent abuse.
Literature and drama are proof of aesthetic work.
Monkeycoin uses attempting to write the complete works of Shakespeare as its proof of work. This is implemented by converting SHA-256 digests to ASCII and checking the results against the first few characters of the First Folio (after dedications and credits), which is is the start of "The Tempest".
The difficulty is increased by requiring successively more characters to be matched.