Watchmen teaser
Yesterday I liked this site called “6 minutes to midnight”, for the upcoming Watchmen film. I’m not very much a fan of these comic series but it looked interesting to me the way of displaying a teaser trailer, through Rorschach (the name of one of the vigilantes) tests that allow (each) you to get previously unseen content and revealing more info about the film in (i think) a catchy way for the real fans.
As for the words (spoiler, for sure), these are the ones that worked for me: smile, hat, guns, woman, helicopter and glasses.
There is also some interaction giving your phone number if you live in the US (allegedly you’ll receive a phone call from Rorschach character), so i couldn’t check exactly what is that about, so if someone would be so nice as to tell the rest of us not living there… 
These phone call campaigns are becoming more and more popular. The new Saw movie used it, as well as the Afro Samurai video game where you would receive a call from Samuel Jackson.