Listen to The Mystery (LibriVox NaNoWriMo novel 2006) on your phone!
The idea was to write a whole novel in the month of November, based on the guidelines of the National Novel Writing Month. The twist is that there are up to 30 people writing together, instead of one toiling alone. Each writer signed up to do one section of 1,700+ words, in English. Plot and particulars were agreed before the start. Each writer also recorded his/her own chapter, which can be downloaded here. The resulting novel is in the public domain. (Summary by Gesine)