Around 6 years ago I made a site called the World's Largest Petition. The idea was to get enough digital signatures to break the world record for, you guessed it, the world's largest petition.
Without the social connections of today like Facebook and Twitter it didn't really take off, so over the weekend I redid the site to look much nicer and added in social buttons to allow people to share the site with their friends. It is a basic experiment in web virality in today's world of massive social networks. Check it out at worldslargestpetition.com and share it to try and be part of the record.