Daniel Solis and Greg Stolze are game designers who used what he calls a “ransom model” to produce and sell a board game, Meatbot Massacre, on the Internet. Essentially, Stolze announced the game, set up a PayPal account, and then said the game would be released as a free PDF download once the account had received $600 in donations.
The project was announced in January 2005 and reached the $600 level of donations in April — several months ahead of the September 2005 deadline.
They have nice account of their little experiment, including some suggestions for people who want to try the model for themselves.
The only thing that would have made the experience even better would be if they had released the fan-funded game with a Creative Commons license.