The Assemblathon is a collaborative, recurring effort to spur improvements in computational methods for genome assembly. Teams use their own software to assemble one or more genomes that the organizers of the Assemblathon make available (see the rules for more details). All participants have the same amount of time to try to assemble the genomes, and then the organizers evaluate each group's efforts.
Assemblathon 1: A competitive assessment of de novo short read assembly methods. September 16, 2011. Genome Research.
Assemblathon 2: evaluating de novo methods of genome assembly in three vertebrate species. July 22, 2013. GigaScience.