Where's Dexter?

If you like Where's Wally, but prefer mass murder to stripy bobble hats, you'll love this.  Similar to this, it uses the YouTube in-video linking functionality to turn simple videos in to a game.  The marketing team for Dexter also produced one of my favourite ever viral campaigns a year or so ago where you could send people a text message and an email saying that you'd just seen an eerie news story that 'had to be about them'.  You then linked them to a video that was automatically edited (using info you'd provided) so that it described different things about them and suggesting they were next on a serial killer's hitlist.  Check it out here.