The prize:
An all nighter for you and 1500 mates, music by Moby, Trentemoller and Mylo, in the club section of The O2.
The challenge:
To prove your popularity by starting a guest list at thinkyourepopular.com and getting as many of your friends to join it by picture messaging their photo to the site.
The biggest guest list won the prize.
To help everyone spread the word, there were customised Facebook and MySpace banners, a poster generator and email templates. We also invited party promoter Corey Delaney (now Worthington) to share his party planning know how.
Winner of Aug 08 IAB Creative Showcase
Cannes Lions 2009, Cyber Lion Bronze
Top tips from Corey:
Poster generator

Launch emails
Follow up email
Confirmation email

The website's closed now, but here are some hi-res screen grabs.
This is what the virtual guestlist looked like.