WordPress.com have annoiunced they now accept Bitcoin to pay for upgrades like going ad-free or enabling custom design.
Bitcoin is a digital currency that enables instant payments over the internet. Unlike credit cards and PayPal, Bitcoin has no central authority and no way to lock entire countries out of the network. Merchants who accept Bitcoin payments can do business with anyone.
More info: http://en.blog.wordpress.com/2012/11/15/pay-another-way-bitcoin/