Launch a viral marketing campaign for something simple like a site with a bunch of rotating banners on it?

For example, a new search portal or joke / funny picture site?

Do you think starting up a viral marketing campaign from scratch would be hard to do or, easy if enough people jumped on board to help with it?

Your thoughts?

Im thinking this could make a great project for a bunch of us to play around with if there was enough interest in it.

Regards,

Lee