Just added a command to sx to generate embed addresses so you can embed
records of data into the blockchain. That way you can put some data in,
and be the first to make a timestampped record of it in the blockchain.

cat my_sculpture.jpg | sx embed-addr
1N9v8AKBqst9MNceV3gLmFKsgkKv1bZcBU

then send btc to the address. the record will now be on the blockchain.